Mitigation of Traffic Oscillation on Roadway

ABSTRACT

In an example, a method determines a first controllable vehicle traveling along a mitigation road segment of a roadway and determines a control lane in the mitigation road segment. The control lane includes the first controllable vehicle and is impedible by the first controllable vehicle. The method determines a first open lane in the mitigation road segment and applies a target mitigation speed to the first controllable vehicle in the control lane. The first open lane is adjacent to the control lane in the mitigation road segment and the target mitigation speed is based on a traffic state of the first open lane. The target mitigation speed adjusts a traffic stream that flows through the first open lane to mitigate traffic congestion located downstream of the mitigation road segment.

BACKGROUND

The present disclosure relates to mitigating traffic oscillations onroadways, and in a more particular example, mitigating trafficoscillations on roadways using controllable vehicles.

Traffic oscillation is a stop-and-go driving condition in which thevehicles frequently accelerate and decelerate. The acceleration anddeceleration of multiple vehicles due to traffic oscillations oftenresult in excessive fuel consumption and generate a massive amount ofvehicular emissions. Today, some modern systems rely on autonomous andremotely navigable vehicles to manipulate the traffic flow on theroadway to mitigate the traffic oscillation. These existing systemsgenerally require the vehicles to collaboratively block all lanes of theroadway to prevent other vehicles from passing these controllablevehicles to proceed forward, thereby smoothing the traffic oscillation.However, in many situations, the vehicles cannot block all lanes of theroadway. Therefore, other vehicles may perform one or more lane changemaneuvers to shift to one or more lanes unblocked by the blockingvehicles, and then pass these vehicles through the unblocked lanes toproceed forward. Thus, this approach is usually inefficient or eveninapplicable to mitigate the traffic oscillation in these situations. Inaddition, the existing solutions often require a significant number ofremotely navigable vehicles to be present on the roadway to operate.Therefore, it is usually impractical or impossible for these existingsolutions to mitigate the traffic oscillations in multiple trafficcontexts that include insufficient number of navigable vehicles.

SUMMARY

The subject matter described in this disclosure overcomes thedeficiencies and limitations of the existing solutions by providingnovel technology for mitigating the traffic congestion and smoothing thetraffic oscillation on the roadway.

According to one innovative aspect of the subject matter described inthis disclosure, a computer-implemented method comprises: determining afirst controllable vehicle traveling along a mitigation road segment ofa roadway; determining a control lane in the mitigation road segment,the control lane including the first controllable vehicle and beingimpedible by the first controllable vehicle; determining a first openlane in the mitigation road segment, the first open lane being adjacentto the control lane in the mitigation road segment; and applying atarget mitigation speed to the first controllable vehicle in the controllane, the target mitigation speed being based on a traffic state of thefirst open lane, the target mitigation speed adjusting a traffic streamthat flows through the first open lane to mitigate traffic congestionlocated downstream of the mitigation road segment.

In general, another innovative aspect of the subject matter described inthis disclosure may be embodied in computer-implemented methodscomprising: determining a first controllable vehicle and a secondcontrollable vehicle traveling along a mitigation road segment of aroadway; monitoring a distance between the first controllable vehicleand the second controllable vehicle; determining that the distancebetween the first controllable vehicle and the second controllablevehicle satisfies a proximity distance threshold at a current timestamp;responsive to determining that the distance between the firstcontrollable vehicle and the second controllable vehicle satisfies theproximity distance threshold at the current timestamp, determining acontrol lane and an impedible lane in the mitigation road segment, thecontrol lane including the first controllable vehicle and beingimpedible by the first controllable vehicle, the impedible laneincluding the second controllable vehicle and being impedible by thesecond controllable vehicle; determining an open lane in the mitigationroad segment, the open lane being adjacent to the control lane in themitigation road segment; and applying a target mitigation speed to thefirst controllable vehicle in the control lane and the secondcontrollable vehicle in the impedible lane, the target mitigation speedbeing based on a traffic state of the open lane, the target mitigationspeed adjusting a traffic stream that flows through the open lane tomitigate traffic congestion located downstream of the mitigation roadsegment.

In general, another innovative aspect of the subject matter described inthis disclosure may be embodied in systems comprising: one or moreprocessors; one or more memories storing instructions that, whenexecuted by the one or more processors, cause the system to: determine afirst controllable vehicle traveling along a mitigation road segment ofa roadway; determine a control lane in the mitigation road segment, thecontrol lane including the first controllable vehicle and beingimpedible by the first controllable vehicle; determine a first open lanein the mitigation road segment, the first open lane being adjacent tothe control lane in the mitigation road segment; and apply a targetmitigation speed to the first controllable vehicle in the control lane,the target mitigation speed being based on a traffic state of the firstopen lane, the target mitigation speed adjusting a traffic stream thatflows through the first open lane to mitigate traffic congestion locateddownstream of the mitigation road segment.

These and other implementations may each optionally include one or moreof the following features: that the target mitigation speed increases apassing flow rate at which the traffic stream flowing through the firstopen lane passes the first controllable vehicle travelling at the targetmitigation speed in the control lane; that determining a second openlane in the mitigation road segment, and wherein the target mitigationspeed maximizes an overall passing flow rate at which the traffic streamflowing through the first open lane and a traffic stream flowing throughthe second open lane pass the first controllable vehicle travelling atthe target mitigation speed in the control lane; that determining thefirst open lane in the mitigation road segment includes determining oneor more proximate controllable vehicles located proximate to the firstcontrollable vehicle in the mitigation road segment, and determining thefirst open lane in the mitigation road segment, the first open laneexcluding the one or more proximate controllable vehicles and beingunimpedible by the one or more proximate controllable vehicles; thatdetermining a proximate controllable vehicle located proximate to thefirst controllable vehicle in the mitigation road segment, determiningan impedible lane in the mitigation road segment, the impedible laneincluding the proximate controllable vehicle and being impedible by theproximate controllable vehicle, and applying the target mitigation speedto the proximate controllable vehicle in the impedible lane; thatdetermining one or more open lanes and one or more impedible lanes inthe mitigation road segment, the one or more open lanes including thefirst open lane, generating a first traffic diagram associated with theroadway in an unimpeded traffic condition, the control lane and the oneor more impedible lanes in the mitigation road segment being unimpededin the unimpeded traffic condition, generating a second traffic diagramassociated with the one or more open lanes in an impeded trafficcondition, the control lane and the one or more impedible lanes in themitigation road segment being impeded in the impeded traffic condition,determining a target traffic state for an upstream portion of themitigation road segment, the upstream portion of the mitigation roadsegment being located upstream of the first controllable vehicle, anddetermining the target mitigation speed for the first controllablevehicle based on the first traffic diagram associated with the roadwayin the unimpeded traffic condition, the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition, and the target traffic state for the upstream portion of themitigation road segment; that generating the first traffic diagramassociated with the roadway in the unimpeded traffic condition includesmonitoring traffic data of the roadway, computing one or more trafficmetrics associated with the roadway based on the traffic data of theroadway, determining one or more roadway properties of the roadway,generating the first traffic diagram associated with the roadway in theunimpeded traffic condition based on an initial traffic diagram, the oneor more traffic metrics associated with the roadway, and the one or moreroadway properties of the roadway, and wherein the first traffic diagramindicates a relationship between a flow rate and a vehicle density onthe roadway or a relationship between a vehicle speed and the vehicledensity on the roadway in the unimpeded traffic condition; that thetraffic data of the roadway includes one or more of a flow rate, avehicle density, and a vehicle speed associated with a plurality of roadsegments of the roadway at a plurality of timestamps, the one or moretraffic metrics associated with the roadway includes one or more of aroadway capacity, a capacity vehicle density corresponding to theroadway capacity, and a jam vehicle density associated with the roadway,and the one or more roadway properties of the roadway includes one ormore of a speed limit and a number of lanes associated with the roadway;that generating the second traffic diagram associated with the one ormore open lanes in the impeded traffic condition includes monitoringtraffic data of the roadway, computing one or more traffic metricsassociated with the roadway based on the traffic data of the roadway,computing one or more traffic metrics associated with the one or moreopen lanes based on the traffic metrics associated with the roadway anda number of open lanes in the mitigation road segment, determining oneor more roadway properties of the one or more open lanes, generating thesecond traffic diagram associated with the one or more open lanes in theimpeded traffic condition based on an initial traffic diagram, the oneor more traffic metrics associated with the one or more open lanes, andthe one or more roadway properties of the one or more open lanes, andwherein the second traffic diagram indicates a relationship between aflow rate and a vehicle density in the one or more open lanes or arelationship between a vehicle speed and the vehicle density in the oneor more open lanes in the impeded traffic condition; that determiningthe target traffic state for the upstream portion of the mitigation roadsegment includes determining a traffic wave on the roadway and one ormore propagation parameters of the traffic wave, determining a vehicledensity of the mitigation road segment at a current timestamp,estimating an average vehicle density of the mitigation road segment ata future timestamp based on the vehicle density of the mitigation roadsegment at the current timestamp and the one or more propagationparameters of the traffic wave, and determining the target traffic statefor the upstream portion of the mitigation road segment based on theaverage vehicle density of the mitigation road segment at the futuretimestamp; that determining the traffic wave on the roadway and the oneor more propagation parameters of the traffic wave includes receivingvehicle movement data of one or more vehicles located on the roadway ata plurality of timestamps, determining a plurality of vehicle densitydistributions associated with the roadway at the plurality of timestampsbased on the vehicle movement data of the one or more vehicles locatedon the roadway at the plurality of timestamps and the first trafficdiagram associated with the roadway in the unimpeded traffic condition,and determining the traffic wave on the roadway and the one or morepropagation parameters of the traffic wave based on the plurality ofvehicle density distributions associated with the roadway at theplurality of timestamps; that the vehicle movement data of the one ormore vehicles located on the roadway at the plurality of timestampsincludes one or more of a vehicle location, a vehicle speed, and avehicle lane of a vehicle among the one or more vehicles at acorresponding timestamp among the plurality of timestamps, and the oneor more propagation parameters of the traffic wave includes one or moreof a propagation speed, a propagation distance, a coverage area of atraffic stop region associated with the traffic wave, and a coveragearea of a traffic moving region associated with the traffic wave; thatdetermining the vehicle density of the mitigation road segment at thecurrent timestamp includes receiving vehicle movement data of a vehicle,the vehicle movement data including a vehicle speed of the vehicle at avehicle location in the mitigation road segment at the currenttimestamp, and determining the vehicle density of the mitigation roadsegment at the current timestamp based on the vehicle speed of thevehicle at the current timestamp and the first traffic diagramassociated with the roadway in the unimpeded traffic condition; thatdetermining the target traffic state for the upstream portion of themitigation road segment includes determining the target traffic state onthe first traffic diagram associated with the roadway in the unimpededtraffic condition based on an average vehicle density of the mitigationroad segment at a future timestamp, and wherein the target mitigationspeed transitions the upstream portion of the mitigation road segment tothe target traffic state having the average vehicle density of themitigation road segment at the future timestamp; that determining thetarget mitigation speed for the first controllable vehicle includesdetermining a tangent line including the target traffic state on thefirst traffic diagram associated with the roadway in the unimpededtraffic condition and being tangent to the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition, determining an initiation traffic state of the one or moreopen lanes on the second traffic diagram associated with the one or moreopen lanes in the impeded traffic condition based on the tangent line,the traffic state of the first open lane being the initiation trafficstate of the one or more open lanes, and determining the targetmitigation speed for the first controllable vehicle based on a slope ofa state transition line, the state transition line including theinitiation traffic state on the second traffic diagram associated withthe one or more open lanes in the impeded traffic condition and thetarget traffic state on the first traffic diagram associated with theroadway in the unimpeded traffic condition.

These and other implementations may each optionally include one or moreof the following features: that determining the first controllablevehicle that has a distance between the first controllable vehicle andthe traffic congestion satisfying a congestion distance threshold, anddetermining the second controllable vehicle that has a distance betweenthe second controllable vehicle and the first controllable vehiclesatisfying an initial vehicle distance threshold.

Other implementations of one or more of these and other aspects includecorresponding systems, apparatus, and computer programs, configured toperform the actions of methods, encoded on non-transitory computerstorage devices.

The novel technology for mitigating traffic congestions and smoothingtraffic oscillations on roadway in this disclosure is particularlyadvantageous in a number of respects. For example, the technologydescribed herein is capable of efficiently addressing traffic congestionand mitigating traffic oscillations even if one or more vehicles mayperform lane change maneuvers and/or passing behaviors in one or morelanes of the roadway. Thus, the present technology can flexibly resolvethe traffic congestion and smooth the traffic oscillation on the roadwayincluding multiple lanes in a variety of traffic contexts. As a furtherexample, the present technology is capable of addressing trafficcongestion and mitigating traffic oscillations with a singlecontrollable vehicle travelling in one lane of the roadway. Therefore,the present technology is advantageously applicable even if the trafficflow on the roadway includes only a limited number of controllablevehicles. Furthermore, the technology described herein can adjust thevehicle movements of both controllable vehicles and other vehicles toresolve the traffic congestion and smooth the traffic oscillation. Asthe traffic congestion is addressed and the traffic oscillation ismitigated, the traffic flow of the entire roadway can be facilitated andthe overall vehicle energy efficiency can be significantly improved.

It should be understood that the foregoing advantages are provided byway of example and that the technology may have numerous otheradvantages and benefits.

The disclosure is illustrated by way of example, and not by way oflimitation in the figures of the accompanying drawings in which likereference numerals are used to refer to similar elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example system for addressing trafficcongestion and mitigating traffic oscillation on a roadway.

FIG. 2 is a block diagram of an example traffic mitigation application.

FIG. 3 is a flowchart of an example method for addressing trafficcongestion and mitigating traffic oscillation.

FIG. 4 is a flowchart of an example method for determining a targetmitigation speed for a controllable vehicle.

FIG. 5 is a flowchart of an example method for generating a trafficmodel associated with a mitigation road segment of the roadway.

FIG. 6 is a flowchart of an example method for determining a targettraffic state for an upstream portion of the mitigation road segment.

FIG. 7 is a flowchart of an example method for determining a trafficwave on the roadway and propagation parameters of the traffic wave.

FIG. 8 is a flowchart of another example method for addressing trafficcongestion and mitigating traffic oscillation.

FIG. 9A illustrates an example traffic model associated with themitigation road segment of the roadway.

FIG. 9B illustrates an example vehicle passing model associated with themitigation road segment of the roadway.

FIG. 10A illustrates an example traffic congestion situation on theroadway.

FIG. 10B illustrates an example of adjusted traffic streams on theroadway to address traffic congestion and mitigate traffic oscillations.

DESCRIPTION

The technology described herein can mitigate traffic congestion and/orsmooth traffic oscillations on the roadways. As described in furtherdetail below, the technology includes various aspects, such as trafficmitigating methods, systems, computing devices, computer programproducts, and apparatuses, among other aspects.

An example traffic mitigating system can determine traffic congestion ona roadway, determine a first controllable vehicle travelling along amitigation road segment of a roadway, and determine one or moreproximate controllable vehicles located proximate to the firstcontrollable vehicle. The traffic mitigating system can determine acontrol lane including the first controllable vehicle and beingimpedible by the first controllable vehicle, one or more impedible lanesincluding the one or more proximate controllable vehicles and beingimpedible by the one or more proximate controllable vehicles, and one ormore open lanes being unimpedible in the mitigation road segment. Thetraffic mitigating system can determine a target mitigation speed forthe first controllable vehicle, and apply the target mitigation speed tothe first controllable vehicle in the control lane and/or the one ormore proximate controllable vehicles in the one or more impedible lanes.As the first controllable vehicle may travel in the control lane and theone or more proximate controllable vehicles may travel in the one ormore impedible lanes at the target mitigation speed, the traffic flowthat passes the first controllable vehicle and/or the one or moreproximate controllable vehicles through the one or more open lanes toreach the congested area can be adjusted, thereby mitigating trafficcongestion and/or smoothing traffic oscillations.

FIG. 1 is a block diagram of an example system 100 for addressingtraffic congestion and/or mitigating traffic oscillations on roadways.As shown, the system 100 includes a server 101 and one or more trafficmonitoring device 109 a . . . 109 n coupled for electronic communicationvia a network 105. The system 100 also includes one or more controllablevehicles 103 a . . . 103 n that are capable of being controlled tomitigate the traffic congestion. The controllable vehicles 103 a . . .103 n are communicatively coupled to the other entities of the system100.

A controllable vehicle 103 includes one or more computing devices 152having sensor(s) 113, processor(s) 115, memory(ies) 117, communicationunit(s) 119, a vehicle data store 121, and/or a traffic mitigationapplication 120. Examples of computing device(s) 152 may include virtualor physical computer processors, control units, micro-controllers, etc.,which are coupled to other components of the controllable vehicle(s)103, such as one or more sensors 113, one or more actuators, one or moremotivators, etc.

A controllable vehicle 103 is a vehicle that is capable of controllingone or more aspects of the vehicle independent of a human driver of thevehicle. For example, the controllable vehicle can adjust dynamicaspects of the vehicle, such as the speed, acceleration, steering,braking, suspension, etc., of the vehicle independent of a human driverof the vehicle. For instance, a processor 115 of the controllablevehicle 103 may control various actuators and/or motivators (e.g.,comprising the fuel system, engine, brake system, steering system, etc.)to regulate the movement and speed of the vehicle 103.

The controllable vehicle is responsive to instructions generated by anon-board processor and/or received via a computer network (e.g., via awireless network). The controllable vehicle(s) 103 may be coupled to thenetwork 105 via signal line 141, and may send and receive data via anetwork. For example, a controllable vehicle 103 may send and receivedata to and from other controllable vehicle(s) 103, the trafficmonitoring device(s) 109, the responsive vehicle(s) 107, and/or theserver(s) 101. Non-limiting examples of the controllable vehicle(s) 103include an automobile, a bus, a truck, a boat, a plane, a bionicimplant, a robot, a drone, or any other suitable moving platformscapable of navigating from one point to another over land, water, air,space, etc.

The system 100 also includes one or more uncontrollable vehicles 107 a .. . 107 n that lack the capability of being controlled to mitigate thetraffic congestion, or have the capability but are restricted from orincapable of using it when needed due to various reasons (e.g., systemerrors, power loss, opt-out settings, etc.). The uncontrollable vehicles107 a . . . 107 n may include one or more responsive vehicles 107communicatively coupled to the other entities of the system 100 (asreflected by the signal line 143) and one or more non-responsivevehicles 107 that are not communicatively coupled to the other entitiesof the system 100. The controllable vehicles 103 a . . . 103 n and theuncontrollable vehicles 107 a . . . 107 n may be referred to herein asvehicle(s) in some cases.

In FIG. 1 and the remaining figures, a letter after a reference number,e.g., “103 a,” represents a reference to the element having thatparticular reference number. A reference number in the text without afollowing letter, e.g., “103,” represents a general reference toinstances of the element bearing that reference number. It should beunderstood that the system 100 depicted in FIG. 1 is provided by way ofexample and the system 100 and/or further systems contemplated by thispresent disclosure may include additional and/or fewer components, maycombine components and/or divide one or more of the components intoadditional components, etc. For example, the system 100 may include anynumber of controllable vehicles 103, uncontrollable vehicles 107,traffic monitoring devices 109, networks 105, or servers 101.

The network 105 may be a conventional type, wired and/or wireless, andmay have numerous different configurations including a starconfiguration, token ring configuration, or other configurations. Forexample, the network 105 may include one or more local area networks(LAN), wide area networks (WAN) (e.g., the Internet), personal areanetworks (PAN), public networks, private networks, virtual networks,virtual private networks, peer-to-peer networks, near field networks(e.g., Bluetooth®, NFC, etc.), vehicular networks, and/or otherinterconnected data paths across which multiple devices may communicate.

The network 105 may also be coupled to or include portions of atelecommunications network for sending data in a variety of differentcommunication protocols. Example protocols include, but are not limitedto, transmission control protocol/Internet protocol (TCP/IP), userdatagram protocol (UDP), transmission control protocol (TCP), hypertexttransfer protocol (HTTP), secure hypertext transfer protocol (HTTPS),dynamic adaptive streaming over HTTP (DASH), real-time streamingprotocol (RTSP), real-time transport protocol (RTP) and the real-timetransport control protocol (RTCP), voice over Internet protocol (VOIP),file transfer protocol (FTP), WebSocket (WS), wireless access protocol(WAP), various messaging protocols (SMS, MMS, XMS, IMAP, SMTP, POP,WebDAV, etc.), or other suitable protocols. In some embodiments, thenetwork 105 is a wireless network using a connection such as DSRC(Dedicated Short Range Communication), WAVE, 802.11p, a 3G, 4G, 5G+network, WiFi™, satellite networks, vehicle-to-vehicle (V2V) networks,vehicle-to-infrastructure/infrastructure-to-vehicle (V2I/I2V) networks,or any other wireless networks. Although FIG. 1 illustrates a singleblock for the network 105 that couples to the server 101, the trafficmonitoring device(s) 109, the controllable vehicle(s) 103, and theresponsive vehicle(s) 107, it should be understood that the network 105may in practice comprise any number of combination of networks, as notedabove.

The server 101 includes a hardware and/or virtual server that includes aprocessor, a memory, and network communication capabilities (e.g., acommunication unit). The server 101 may be communicatively coupled tothe network 105, as reflected by signal line 145. In some embodiments,the server may send and receive data to and from other entities of thesystem 100, e.g., the controllable vehicle(s) 103, the responsivevehicle(s) 107, and/or the traffic monitoring device(s) 109. Asdepicted, the server 101 may include an instance 120 a of a trafficmitigation application 120 as further discussed elsewhere herein.

The traffic monitoring device(s) 109 a . . . 109 n include a hardwareand/or virtual device that includes a processor, a memory, and networkcommunication capabilities (e.g., a communication unit). The trafficmonitoring device(s) 109 may be communicatively coupled to the network105, as reflected by signal line 147. In some embodiments, the trafficmonitoring device(s) 109 may be the monitoring device(s) mounted at ahigh position and/or located on the roadside of various road segments ofthe roadway to monitor the traffic on the roadway and generate trafficdata describing the traffic on the roadway. In some embodiments, thetraffic data of the roadway may include the flow rate, the vehicledensity, the vehicle speed, etc. associated with various road segmentsof the roadway at multiple timestamps. Other types of traffic data arealso possible and contemplated.

In some embodiments, each traffic monitoring device 109 may monitor acorresponding road segment of the roadway, generate traffic data for thecorresponding road segment, and send the traffic data associated withthe corresponding road segment as the traffic data of the roadway toother entities of the system 100 (e.g., the controllable vehicle(s) 103,the server 101, etc.). In some embodiments, the traffic monitoringdevice 109 may include one or more image sensors (e.g., surveillancecameras) configured to capture images of the corresponding road segmentwithin their sensor range, and one or more processing units configuredto analyze the captured images to generate the traffic data associatedwith the corresponding road segment. As an example, the trafficmonitoring device 109 may perform image processing on the capturedimages to determine the number of vehicles travelling on thecorresponding road segment that pass the traffic monitoring device 109in a predefined time period (e.g., 5 s), and compute the flow rateassociated with the corresponding road segment accordingly. It should beunderstood that other implementations for monitoring the traffic on theroadway and generating the traffic data of the roadway are also possibleand contemplated.

The processor(s) 115 may execute software instructions (e.g., tasks) byperforming various input/output, logical, and/or mathematicaloperations. The processor(s) 115 may have various computingarchitectures to process data signals. The processor(s) 115 may bephysical and/or virtual, and may include a single core or plurality ofprocessing units and/or cores. In the context of the controllablevehicle 103, the processor may be an electronic control unit (ECU)implemented in the controllable vehicle 103 such as a car, althoughother types of platform are also possible and contemplated. The ECUs mayreceive and store the sensor data as vehicle operation data in thevehicle data store 121 for access and/or retrieval by the trafficmitigation application 120. In some implementations, the processor(s)115 may be capable of generating and providing electronic displaysignals to input/output device(s), supporting the display of images,generating and transmitting vehicle movement data, performing complextasks including various types of traffic condition analysis and optimalspeed computation, etc. In some implementations, the processor(s) 115may be coupled to the memory(ies) 117 via the bus 154 to access data andinstructions therefrom and store data therein. The bus 154 may couplethe processor(s) 115 to the other components of the controllablevehicle(s) 103 including, for example, the sensor(s) 113, thememory(ies) 117, the communication unit(s) 119, and/or and the vehicledata store 121.

The traffic mitigation application 120 includes software and/or hardwarelogic executable to resolve traffic congestion and mitigate trafficoscillation. As illustrated in FIG. 1, the server 101 and thecontrollable vehicle 103 a . . . 103 n may include instances 120 a and120 b. . . 120 n of the traffic mitigation application 120. In someembodiments, each instance 120 a and 120 b . . . 120 n may comprise oneor more components the traffic mitigation application 120 depicted inFIG. 2, and may be configured to fully or partially perform thefunctionalities described herein depending on where the instanceresides. In some embodiments, the traffic mitigation application 120 maybe implemented using software executable by one or more processors ofone or more computer devices, using hardware, such as but not limited toa field-programmable gate array (FPGA), an application-specificintegrated circuit (ASIC), etc., and/or a combination of hardware andsoftware, etc. The traffic mitigation application 120 may receive andprocess the sensor data, the traffic data, the vehicle movement data,etc., and communicate with other elements of the controllable vehicle103 via the bus 154, such as the memory 117, the communication unit 119,the vehicle data store 121, and various actuators and/or motivators,etc. For example, the traffic mitigation application 120 may communicatea target mitigation speed to one or more speed actuators of thecontrollable vehicle 103 to control the vehicle movement of thecontrollable vehicle 103, thereby mitigating traffic congestion andsmoothing traffic oscillation on the roadway. The traffic mitigationapplication 120 is described in details below with reference to at leastFIGS. 2-10B.

The memory(ies) 117 includes a non-transitory computer-usable (e.g.,readable, writeable, etc.) medium, which can be any tangiblenon-transitory apparatus or device that can contain, store, communicate,propagate, or transport instructions, data, computer programs, software,code, routines, etc., for processing by or in connection with theprocessor(s) 115. For example, the memory(ies) 117 may store the trafficmitigation application 120. In some implementations, the memory(ies) 117may include one or more of volatile memory and non-volatile memory. Forexample, the memory(ies) 117 may include, but is not limited to, one ormore of a dynamic random access memory (DRAM) device, a static randomaccess memory (SRAM) device, a discrete memory device (e.g., a PROM,FPROM, ROM), a hard disk drive, an optical disk drive (CD, DVD,Blue-ray™, etc.). It should be understood that the memory(ies) 117 maybe a single device or may include multiple types of devices andconfigurations.

The communication unit 119 transmits data to and receives data fromother computing devices to which it is communicatively coupled (e.g.,via the network 105) using wireless and/or wired connections. Thecommunication unit 119 may include one or more wired interfaces and/orwireless transceivers for sending and receiving data. The communicationunit 119 may couple to the network 105 and communicate with otherentities of the system 100, such as other controllable vehicle(s) 103,responsive vehicle(s) 107, traffic monitoring device(s) 109, and/orserver(s) 101, etc. The communication unit 119 may exchange data withother computing nodes using standard communication methods, such asthose discussed above.

The sensor(s) 113 includes any type of sensors suitable for thecontrollable vehicle(s) 103. The sensor(s) 113 may be configured tocollect any type of signal data suitable to determine characteristics ofthe controllable vehicle 103 and/or its internal and externalenvironments. Non-limiting examples of the sensor(s) 113 include variousoptical sensors (CCD, CMOS, 2D, 3D, light detection and ranging (LIDAR),cameras, etc.), audio sensors, motion detection sensors, barometers,altimeters, thermocouples, moisture sensors, infrared (IR) sensors,radar sensors, other photo sensors, gyroscopes, accelerometers,speedometers, steering sensors, braking sensors, switches, vehicleindicator sensors, windshield wiper sensors, geo-location sensors (e.g.,GPS (Global Positioning System) sensors), orientation sensor, wirelesstransceivers (e.g., cellular, WiFi™, near-field, etc.), sonar sensors,ultrasonic sensors, touch sensors, proximity sensors, distance sensors,etc. In some embodiments, one or more sensors 113 may include externallyfacing sensors provided at the front side, rear side, right side, and/orleft side of the controllable vehicle 103 to capture the situationalcontext surrounding the controllable vehicle 103.

In some embodiments, the sensor(s) 113 may include one or more imagesensors (e.g., optical sensors) configured to record images includingvideo images and still images, may record frames of a video stream usingany applicable frame rate, and may encode and/or process the video andstill images captured using any applicable methods. In some embodiments,the image sensor(s) can capture images of surrounding environmentswithin their sensor range. For example, in the context of a vehicle, theimage sensors can capture the environment around the controllablevehicle 103 including roads, roadside structures, buildings, static roadobjects (e.g., lanes, road markings, traffic signs, traffic cones,barricades, etc.), and/or dynamic road objects (e.g., surroundingcontrollable vehicles 103 and uncontrollable vehicles 107, road workers,construction vehicles, etc.), etc. In some embodiments, the imagesensors may be mounted on the vehicle roof and/or inside thecontrollable vehicle 103 to sense in any direction (forward, rearward,sideward, upward, downward facing, etc.) relative to the movingdirection of the controllable vehicle 103. In some embodiments, theimage sensors may be multidirectional (e.g., LIDAR).

The vehicle data store 121 includes a non-transitory storage medium thatstores various types of data. For example, the vehicle data store 121may store vehicle data being communicated between different componentsof a given controllable vehicle 103 using a bus, such as a controllerarea network (CAN) bus. In some embodiments, the vehicle data mayinclude vehicle operation data collected from multiple sensors 113coupled to different components of the controllable vehicle 103 formonitoring operating states of these components, e.g., transmission,vehicle speed, acceleration, deceleration, wheel speed (Revolutions PerMinute—RPM), steering angle, braking force, etc. In some embodiments,the vehicle data may include multiple road scene images captured by oneor more image sensors of the controllable vehicle 103 and the image dataassociated with these images. In some embodiments, these captured imagesmay be processed to determine lane information (e.g., vehicle lane inwhich the controllable vehicle 103 travels, etc.) and/or otherinformation of the controllable vehicle 103.

In some embodiments, the vehicle data store 121 may store vehiclemovement data describing the vehicle movement of the controllablevehicle 103 at multiple timestamps. For each timestamp, the vehiclemovement data of the controllable vehicle 103 may include the vehiclespeed, the vehicle location indicating the geographic location of thecontrollable vehicle 103 (e.g., GPS coordinates), the vehicle laneindicating the lane in which the controllable vehicle 103 travels, etc.,at the corresponding timestamp. Other types of vehicle movement data arealso possible and contemplated. In some embodiments, each controllablevehicle 103 may periodically transmit its vehicle movement data to othercontrollable vehicles 103 and the responsive vehicles 107 located withinits communication range and/or to the server 101 (e.g., every 2 s). Thecontrollable vehicle 103 may also receive the vehicle movement datadescribing the vehicle movement of other controllable vehicles 103 andthe responsive vehicles 107 at multiple timestamps, and store thevehicle movement data of these vehicles in the vehicle data store 121.

In some embodiments, the vehicle data store 121 may store traffic datadescribing the traffic on various road segments of the roadway atmultiple timestamps. For each road segment of the roadway at eachtimestamp, the traffic data of the roadway may include the vehicledensity indicating the number of vehicles present on a predefineddistance of the road segment at the corresponding timestamp (e.g., 40vehicles/km), the flow rate indicating the number of vehicles passing astatic point of observation on the road segment in a predefined timeperiod at the corresponding timestamp (e.g., 4000 vehicles/h), thevehicle speed indicating the average speed of the vehicles travelling onthe road segment at the corresponding timestamp (e.g., 100 km/h), etc.Other types of traffic data are also possible and contemplated.

In some embodiments, the vehicle data store 121 may also store trafficmetrics indicating various properties of the traffic flow on theroadway. In some embodiments, the traffic metrics may include theroadway capacity (e.g., 5400 vehicles/hour), the capacity vehicledensity (e.g., 60 vehicles/km), the jam vehicle density (e.g., 180vehicles/km), etc., associated with the roadway. Other traffic metricsare also possible and contemplated.

In some embodiments, the vehicle data store 121 may store one or moretraffic models, and one or more vehicle passing models corresponding tothe one or more traffic models. In some embodiments, the traffic modelmay describe the traffic flow on the roadway and the traffic flow in oneor more open lanes of the roadway. In some embodiments, the traffic flowon the roadway may include one or more traffic streams and each trafficstream may flow through one lane of the roadway. Similarly, the trafficflow in the one or more open lanes of the roadway may include one ormore traffic streams and each traffic stream may flow through one openlane of the roadway. In some embodiments, the vehicle passing modelcorresponding to the traffic model may describe the traffic flow on theroadway and the traffic flow in the one or more open lanes of theroadway relative to a controllable vehicle 103 moving at a vehiclespeed, and thus describing the passing flow that passes thiscontrollable vehicle 103.

In some embodiments, the vehicle data store 121 may store the initialtraffic condition diagram, the roadway properties of the roadway (e.g.,speed limit, number of lanes, etc.), the roadway properties of the oneor more open lanes of the roadway (e.g., number of open lanes, etc.),and/or other types of data for generating the traffic models and/or thevehicle passing models. In some embodiments, the vehicle data store 121may also store the target mitigation speed for controlling the vehiclemovement of one or more controllable vehicles 103 to mitigate trafficcongestion and smooth traffic oscillations.

In some embodiments, the vehicle data store 121 may be part of a datastorage system (e.g., a standard data or database management system) forstoring and providing access to data. Other types of data stored in thevehicle data store 121 are also possible and contemplated.

Other variations and/or combinations are also possible and contemplated.It should be understood that the system 100 illustrated in FIG. 1 isrepresentative of an example system and that a variety of differentsystem environments and configurations are contemplated and are withinthe scope of the present disclosure. For instance, various acts and/orfunctionality may be moved from a server to a client, or vice versa,data may be consolidated into a single data store or further segmentedinto additional data stores, and some implementations may includeadditional or fewer computing devices, services, and/or networks, andmay implement various functionality client or server-side. Further,various entities of the system may be integrated into a single computingdevice or system or divided into additional computing devices orsystems, etc.

FIG. 2 is a block diagram of an example traffic mitigation application120. As depicted, the traffic mitigation application 120 may include atraffic mitigation initiator 202, a model generator 204, a trafficoscillation analyzer 206, and a target speed calculator 208, although itshould be understood that the traffic mitigation application 120 mayinclude additional components such as, but not limited to, aconfiguration engine, a training engine, an encryption/decryptionengine, etc., and/or these various components may be combined into asingle engine or divided into additional engines.

The traffic mitigation initiator 202, the model generator 204, thetraffic oscillation analyzer 206, and the target speed calculator 208may be implemented as software, hardware, or a combination of theforegoing. In some embodiments, the traffic mitigation initiator 202,the model generator 204, the traffic oscillation analyzer 206, and thetarget speed calculator 208 may be communicatively coupled by the bus154 and/or the processor 115 to one another and/or the other componentsof the computing device 152. In some embodiments, one or more of thecomponents 120, 202, 204, 206, and/or 208 are sets of instructionsexecutable by the processor 115 to provide their functionality. Infurther embodiments, one or more of the 120, 202, 204, 206, and/or 208are storable in the memory 117 and are accessible and executable by theprocessor 115 to provide their functionality. In any of the foregoingembodiments, these components 120, 202, 204, 206, and/or 208 may beadapted for cooperation and communication with the processor 115 andother components of the computing device 152. The traffic mitigationapplication 120, and its components 202, 204, 206, and 208 are describedin further detail below with reference to at least FIGS. 3-10B.

As discussed elsewhere herein, the traffic mitigation application 120includes logic executable to determine target mitigation speed for oneor more controllable vehicles 103 to resolve traffic congestion andsmooth traffic oscillation on a roadway. As an example, a generaltraffic congestion situation 1000 is illustrated in FIG. 10A. As shown,FIG. 10A depicts a roadway 1010 including a congested area 1012 in whichtraffic congestion occurs and a traffic moving area 1014 in which thevehicles can still proceed. The traffic moving area 1014 may be locatedupstream of the congested area 1012 in the moving direction 1015 of theroadway 1010. As depicted, the roadway 1010 includes 4 lanes (e.g., lane1003, lane 1005, lane 1007, lane 1009). Thus, the traffic flow on theroadway 1010 may include 4 traffic streams, each traffic stream may flowthrough one lane of the roadway 1010. The roadway 1010 may also beprovided with multiple traffic monitoring devices 109 located along theroadway 1010. As discussed elsewhere herein, the traffic monitoringdevices 109 may monitor the traffic and generate the traffic datadescribing the traffic on the roadway 1010 at multiple timestamps.

As illustrated in FIG. 10A, the vehicles may travel in each lane of theroadway 1010 in the moving direction 1015. In some embodiments, thevehicles travelling on the roadway 1010 may include one or morecontrollable vehicles 103 and one or more uncontrollable vehicles 107.The controllable vehicle 103 may have the capability and/or permissionof its owner to communicate the vehicle movement data, the traffic data,etc., to and from other responsive entities (e.g., other controllablevehicles 103, the responsive vehicles 107, the traffic monitoringdevices 109, the server 101, etc.), may receive or compute the targetmitigation speed, and may adjust its vehicle speed to the targetmitigation speed to mitigate traffic congestion and smooth trafficoscillations.

On the other hand, the uncontrollable vehicle 107 may be unable to orincapable of receiving or computing the target mitigation speed andadjusting its vehicle speed to the target mitigation speed to mitigatetraffic congestion and smooth traffic oscillations. In this presentdisclosure, the controllable vehicles 103 may be indicated by referencenumbers with prefix “C” (controllable). For example, as shown in FIG.10A, the vehicles travelling in the lane 1005 of the roadway 1010 is arandom mixture of the controllable vehicles C1052, C1050, C1054, and theuncontrollable vehicles 107 b-107 g. Among these uncontrollable vehicles107, the uncontrollable vehicles 107 c, 107 d, 107 g may be responsivevehicles 107 (that are restricted from being controlled or areunutilized/unneeded) while the uncontrollable vehicles 107 b, 107 e, 107f may be the non-responsive vehicles 107.

As a vehicle travels along the roadway 1010, the vehicle may perform oneor more passing behaviors. For example, a vehicle travelling in one lanemay pass one or more vehicles travelling in other lanes of the roadway1010 due to its higher vehicle speed. The vehicle may also perform apassing maneuver to pass one or more vehicles travelling in its currentlane. As an example, in the traffic context depicted in FIG. 10A, thecontrollable vehicle C1050 may travel in the lane 1005 at a lowervehicle speed as compared to other vehicles in other lanes. Thus, theuncontrollable vehicle 107 a travelling in the lane 1007 may pass thecontrollable vehicle C1050 travelling in the lane 1005. In this example,the controllable vehicle C1052 in the lane 1005 may perform a passingmaneuver to pass other vehicles travelling in front of it in the lane1005. For example, when there is sufficient space in the lane 1007, thecontrollable vehicle C1052 may perform a lane change maneuver to shiftfrom the lane 1005 to the lane 1007, pass the uncontrollable vehicle 107b and the controllable vehicle C1050 travelling in the lane 1005 as thecontrollable vehicle C1052 travels in the lane 1007, and then performanother lane change maneuver to shift from the lane 1007 back to thelane 1005. As a result of this passing maneuver, the controllablevehicle C1052 may pass from the vehicle location behind theuncontrollable vehicle 107 b in the lane 1005 to the vehicle location infront of the controllable vehicle C1050 in the lane 1005. Alternatively,after passing the uncontrollable vehicle 107 b and the controllablevehicle C1050, the controllable vehicle C1052 may continue travelling inthe lane 1007 or perform another lane change maneuver to shift from thelane 1007 to a different lane of the roadway 1010 (e.g., the lane 1009).In this present disclosure, the passing behavior of the vehicle mayrefer to any passing maneuvers performed by the uncontrollable vehicle107 b and the controllable vehicle C1052 described in the above example.Other types of passing behavior are also possible and contemplated.

FIG. 3 is a flowchart of an example method 300 for addressing trafficcongestion and mitigating traffic oscillations. In block 302, thetraffic mitigation initiator 202 may determine a first controllablevehicle 103 traveling along a mitigation road segment of a roadway. Insome embodiments, to determine the first controllable vehicle 103traveling along the mitigation road segment, the traffic mitigationinitiator 202 may determine traffic congestion on the roadway. Forexample, the traffic mitigation initiator 202 may analyze the trafficdata of the roadway, determine a congested area on the roadway that hasthe flow rate in the congested area satisfying the congested flow ratethreshold (e.g., less than 20 vehicles/hour), and thus determine thattraffic congestion is present in the congested area. In the exampledepicted in FIG. 10A, the traffic mitigation initiator 202 may determinethat the congested area 1012 of the roadway 1010 is in fact congested.In some embodiments, the traffic mitigation initiator 202 may alsodetermine the geographic location (e.g., GPS coordinates) of thecongested area. The geographic location of the congested area may bereferred to as the geographic location of the traffic congestion. Insome embodiments, the traffic mitigation initiator 202 may receiveinformation describing the traffic congestion from other entities (e.g.,the server 101, the traffic monitoring device 109, etc.).

In some embodiments, the traffic mitigation initiator 202 may determinethe first controllable vehicle 103 located upstream of the trafficcongestion, the first controllable vehicle 103 may have the distancebetween the first controllable vehicle 103 and the traffic congestionsatisfying a congestion distance threshold (e.g., more than 45 m). Insome embodiments, the traffic mitigation initiator 202 may determinemultiple controllable vehicles 103 located upstream of the trafficcongestion that has the distance to the traffic congestion satisfyingthe congestion distance threshold, and randomly select the firstcontrollable vehicle 103 among these multiple controllable vehicles 103.In some embodiments, the traffic mitigation initiator 202 may determinethe controllable vehicle 103 that has the lowest distance to the trafficcongestion among these multiple controllable vehicles 103, and determinethis controllable vehicle 103 to be the first controllable vehicle 103.Other implementations for determining the first controllable vehicle 103are also possible and contemplated.

In some embodiments, the traffic mitigation initiator 202 may determinethe mitigation road segment associated with the first controllablevehicle 103. As discussed in detail below, the first controllablevehicle 103 may travel along the mitigation road segment and adjust thetraffic streams flowing through one or more lanes of the mitigation roadsegment to mitigate the traffic congestion and smooth the trafficoscillation. In some embodiments, the traffic mitigation initiator 202may determine the mitigation road segment located upstream of thetraffic congestion, the mitigation road segment may have a predefinedcoverage area (e.g., 60 m) with the first controllable vehicle 103located at a predefined position relative to the mitigation road segment(e.g., center point, 20m from the start point of the mitigation roadsegment, etc.).

In some embodiments, the traffic mitigation initiator 202 may determinethe mitigation road segment based on the traffic waves on the roadway.As discussed elsewhere herein, the traffic oscillation analyzer 206 maydetermine one or more traffic waves on the roadway and one or moreoscillation cycles of the traffic waves. Each oscillation cycle of thetraffic wave may include a traffic stop region in which the vehiclescannot move forward and a traffic moving region in which the vehiclescan still move forward. In some embodiments, the traffic mitigationinitiator 202 may determine the mitigation road segment that includesthe first controllable vehicle 103 therein and has the coverage area ofthe mitigation road segment including one or more oscillation cycles ofthe traffic waves. Other implementations for determining the mitigationroad segment associated with the first controllable vehicle 103 are alsopossible and contemplated.

Continuing the example in FIG. 10A, the traffic mitigation initiator 202may determine the first controllable vehicle 103 to be the controllablevehicle C1050 travelling in the lane 1005 of the roadway 1010. In thisexample, the traffic mitigation initiator 202 may also determine themitigation road segment to be the mitigation road segment 1020. Asdepicted in FIG. 10A, the mitigation road segment 1020 may be locatedupstream of the traffic congestion in the congested area 1012, and thefirst controllable vehicle C1050 may travel in the lane 1005 along themitigation road segment 1020.

In block 304, the traffic mitigation initiator 202 may determine acontrol lane in the mitigation road segment, the control lane mayinclude the first controllable vehicle 103 and may be impedible by thefirst controllable vehicle 103. For example, the first controllablevehicle 103 may be controlled to travel in the control lane at a vehiclespeed lower than the vehicle speed of surrounding vehicles in otherlanes, and thus impeding the traffic stream behind the firstcontrollable vehicle 103 in the control lane as compared to the trafficstreams flowing through the other lanes in the mitigation road segment.Continuing the example in FIG. 10A, the traffic mitigation initiator 202may determine the control lane to be the lane 1005 including the firstcontrollable vehicle C1050.

In block 306, the traffic mitigation initiator 202 may optionallydetermine one or more impedible lanes in the mitigation road segment,the impedible lanes may be distinct from the control lane. In someembodiments, to determine the impedible lane, the traffic mitigationinitiator 202 may determine the proximate controllable vehicle(s) 103located proximate to the first controllable vehicle 103 in themitigation road segment, and determine the impedible lane including oneor more proximate controllable vehicles 103. Thus, similar to thecontrol lane being impedible by the first controllable vehicle 103, theimpedible lane may be impedible by the proximate controllable vehicle103 included in the impedible lane.

In some embodiments, to determine the proximate controllable vehicle103, the traffic mitigation initiator 202 may determine the controllablevehicle 103 that has the distance between the controllable vehicle 103and the first controllable vehicle 103 in the control lane satisfying aproximate distance threshold (e.g., less than 5m), and determine thiscontrollable vehicle 103 to be the proximate controllable vehicle 103.As the proximate controllable vehicle 103 in the impedible lane islocated proximate to the first controllable vehicle 103 in the controllane, the proximate controllable vehicle 103 may be controlled togetherwith the first controllable vehicle 103 to collaboratively mitigate thetraffic congestion. This implementation is particularly advantageousbecause it can reduce the amount of time needed to mitigate the trafficcongestion due to the larger number of lanes in which the trafficstreams are impeded. However, it should be understood that the trafficmitigation application 120 is capable of mitigating the trafficcongestion even if only the first controllable vehicle 103 in thecontrol lane is controlled to impede/regulate the traffic stream flowingthrough the control lane, while the proximate controllable vehicles 103in the impedible lanes are not controlled and therefore the trafficstreams flowing through these impedible lanes are not impeded.

Continuing the example in FIG. 10A, the traffic mitigation initiator 202may determine that the distance along the moving direction 1015 of theroadway 1010 between the controllable vehicle C1030 and the firstcontrollable vehicle C1050, and the distance along the moving direction1015 between the controllable vehicle C1090 and the first controllablevehicle C1050 satisfy the proximate distance threshold (e.g., less than5m). Thus, the traffic mitigation initiator 202 may determine thecontrollable vehicle C1030 and the controllable vehicle C1090 to be theproximate controllable vehicles 103 located proximate to the firstcontrollable vehicle C1050. As shown, the proximate controllable vehicleC1030 may be located downstream of the first controllable vehicle C1050while the proximate controllable vehicle C1090 may be located upstreamof the first controllable vehicle C1050. In this example, the trafficmitigation initiator 202 may determine the lane 1003 including theproximate controllable vehicle C1030 to be the first impedible lane andthe lane 1009 including the proximate controllable vehicle C1090 to bethe second impedible lane in the mitigation road segment 1020.

In block 308, the traffic mitigation initiator 202 may determine one ormore open lanes in the mitigation road segment, the open lane may bedistinct from the control lane and the impedible lanes. In someembodiments, the open lane may be directly adjacent or indirectlyadjacent to the control lane (e.g., the open lane and the control lanemay or may not have other lane(s) located therebetween). In someembodiments, the traffic mitigation initiator 202 may determine theproximate controllable vehicle(s) 103 located proximate to the firstcontrollable vehicle 103 in the mitigation road segment as discussedabove, and determine the open lane that excludes these proximatecontrollable vehicle(s) 103. As the open lane is distinct from thecontrol lane and excludes the proximate controllable vehicles 103, theopen lane may be unimpedible by the first controllable vehicle 103 andthe proximate controllable vehicles 103, and thus the traffic streamflowing through the open lane cannot be impeded in the mitigation roadsegment. It should be understood that the mitigation road segment mayinclude multiple open lanes and these open lanes may be directly orindirectly adjacent to one another (e.g., two open lanes may or may nothave the control lane and/or the impedible lane(s) locatedtherebetween).

Continuing the example in FIG. 10A, the traffic mitigation initiator 202may determine that the lane 1007 does not include the first controllablevehicle C1050, or any of the proximate controllable vehicle C1030 andthe proximate controllable vehicle C1090 located proximate to the firstcontrollable vehicle C1050. Thus, the traffic mitigation initiator 202may determine the lane 1007 to be the open lane in which the trafficstream flowing through the lane 1007 cannot be impeded. Thus, in thisexample, the traffic mitigation initiator 202 may determine that themitigation road segment 1020 includes the control lane 1005, theimpedible lane 1003, the impedible lane 1009, and the open lane 1007.The traffic mitigation initiator 202 may also determine that the trafficstream flowing through the control lane 1005 is impedible by the firstcontrollable vehicle C1050, the traffic stream flowing through theimpedible lane 1003 is impedible by the proximate controllable vehicleC1030, the traffic stream flowing through the impedible lane 1009 isimpedible by the proximate controllable vehicle C1090, and the trafficstream flowing through the open lane 1007 is unimpedible.

In block 310, the traffic mitigation application 120 may apply a targetmitigation speed to the first controllable vehicle 103 in the controllane. In block 312, if the mitigation road segment includes one or moreimpedible lanes, the traffic mitigation application 120 may also applythe target mitigation speed to one or more proximate controllablevehicles 103 in the one or more impedible lanes. As discussed in detailbelow, the target mitigation speed applied to the first controllablevehicle 103 and/or the proximate controllable vehicles 103 may adjustthe traffic streams flowing through the one or more open lanes in themitigation road segment, thereby mitigating the traffic congestionlocated downstream of the mitigation road segment. In some embodiments,the model generator 204, the traffic oscillation analyzer 206, and thetarget speed calculator 208 may determine the target mitigation speedfor the first controllable vehicle 103 based on a traffic state of theone or more open lanes and other factors.

FIG. 4 is a flowchart of an example method 400 for determining thetarget mitigation speed for the first controllable vehicle 103 in thecontrol lane. It should be understood that the method 400 is applicableto determine the target mitigation speed for the first controllablevehicle 103 in various traffic contexts in which the mitigation roadsegment includes at least one open lane and any number of the impediblelanes. In some embodiments, the target mitigation speed applied to thefirst controllable vehicle 103 in the control lane may be lower than thevehicle speed of other vehicles travelling in the one or more open lanesof the mitigation road segment, and thus the first controllable vehicle103 may impede the traffic stream flowing through the control lane ascompared to the traffic streams flowing through the one or more openlanes. Similarly, as the target mitigation speed is applied to theproximate controllable vehicles 103 in the impedible lanes, theproximate controllable vehicles 103 may also impede the traffic streamsflowing through the impedible lanes as compared to the traffic streamsflowing through the one or more open lanes. As a result, the vehiclestravelling behind the first controllable vehicle 103 in the control laneand behind the proximate controllable vehicles 103 in the impediblelanes may likely perform one or more lane change maneuvers when it ispossible to shift to the one or more open lanes. As these vehiclestravel shift to the one or more open lanes, these vehicles may pass thefirst controllable vehicle 103 travelling in the control lane and/or theproximate controllable vehicles 103 travelling in the impedible lanesand proceed with faster movement.

In some embodiments, if the mitigation road segment includes a singleopen lane, the target mitigation speed may increase or maximize thepassing flow rate at which the traffic stream flowing through the onlyopen lane passes the first controllable vehicle 103 and/or the proximatecontrollable vehicles 103 as the first controllable vehicle 103 and/orthe proximate controllable vehicles 103 travel in their correspondinglane at the target mitigation speed. If the mitigation road segmentincludes multiple open lanes, the target mitigation speed may increaseor maximize the overall passing flow rate at which the traffic flowflowing through these multiple open lanes passes the first controllablevehicle 103 and/or the proximate controllable vehicles 103 as the firstcontrollable vehicle 103 and/or the proximate controllable vehicles 103travel in their corresponding lane at the target mitigation speed. Thisimplementation can advantageously mitigate the traffic congestion. Forinstance, to increase or maximize the overall passing flow rate, thefirst controllable vehicle 103 and/or the proximate controllablevehicles 103 may travel at a target mitigation speed that issufficiently low, thereby sufficiently regulating the upstream trafficheading towards the traffic congestion. In addition, as the overallpassing flow rate is increased or maximized, the first controllablevehicle 103 and/or the proximate controllable vehicles 103 travelling atthe target mitigation speed may limit the upstream traffic headingtowards the traffic congestion, while still allow a portion of thisupstream traffic that can be accommodated by the road segment locateddownstream of the mitigation road segment to proceed forward through theone or more open lanes.

In block 402, the model generator 204 may generate a first trafficdiagram associated with the roadway in an unimpeded traffic condition.In the unimpeded traffic condition, the first controllable vehicle 103in the control lane and the proximate controllable vehicles 103 in theone or more impedible lanes may not be controlled with the targetmitigation speed, and therefore the traffic stream flowing through thecontrol lane and the traffic streams flowing through the impedible lanesmay not be impeded in the mitigation road segment. Thus, the trafficstreams flowing through all lanes of the roadway in the mitigation roadsegment (e.g., the control lane, the impedible lane(s), and the openlane(s)) may not be impeded in the unimpeded traffic condition.

In some embodiments, the first traffic diagram associated with theroadway in the unimpeded traffic condition may describe the traffic flowon the roadway (thus, also on the mitigation road segment of theroadway) as all lanes of the roadway are not impeded. In someembodiments, the first traffic diagram may indicate a relationshipbetween the flow rate and the vehicle density on the roadway, and/or arelationship between the vehicle speed and the vehicle density on theroadway in the unimpeded traffic condition. As discussed elsewhereherein, the vehicle density on the roadway may indicate the number ofvehicles present on a predefined distance of the roadway at a particulartimestamp (e.g., 40 vehicles/km), and the flow rate on the roadway mayindicate the number of vehicles travelling on the roadway that pass astatic point of observation in a predefined time period at thecorresponding timestamp (e.g., 4000 vehicles/h).

In block 404, the model generator 204 may generate a second trafficdiagram associated with the one or more open lanes in an impeded trafficcondition. In the impeded traffic condition, the first controllablevehicle 103 in the control lane and the proximate controllable vehicles103 in the one or more impedible lanes may be controlled with the targetmitigation speed, and therefore the first controllable vehicle 103 mayimpede the traffic stream flowing through the control lane and theproximate controllable vehicles 103 may impede the traffic streamsflowing through the one or more impedible lanes in the mitigation roadsegment. Thus, the traffic stream flowing through the control lane inthe mitigation road segment and the traffic streams flowing through theone or more impedible lanes in the mitigation road segment may beimpeded, while the traffic streams flowing through the one or more openlanes in the mitigation road segment may not be impeded in the unimpededtraffic condition.

In some embodiments, the second traffic diagram associated with the oneor more open lanes in the impeded traffic condition may describe trafficflow in the one or more open lanes of the roadway as the control laneand the one or more impedible lanes are impeded while the one or moreopen lanes are not impeded in the mitigation road segment of theroadway. In some embodiments, the second traffic diagram may indicate arelationship between the flow rate and the vehicle density in the one ormore open lanes of the roadway, and/or a relationship between thevehicle speed and the vehicle density in the one or more open lanes ofthe roadway in the impeded traffic condition. Similar to the firsttraffic diagram, the vehicle density in the one or more open lanes ofthe roadway may indicate the number of vehicles present on a predefineddistance of the one or more open lanes at a particular timestamp (e.g.,15 vehicles/km), and the flow rate in the one or more open lanes of theroadway may indicate the number of vehicles travelling in the one ormore open lanes that pass a static point of observation in a predefinedtime period at the corresponding timestamp (e.g., 2700 vehicles/h).

FIG. 5 is a flowchart of an example method 500 for generating a trafficmodel associated with the mitigation road segment of the roadway, thetraffic model may include the first traffic diagram associated with theroadway in the unimpeded traffic condition and the second trafficdiagram associated with the one or more open lanes in the impededtraffic condition. In block 502, the model generator 204 may receivetraffic data of the roadway. For example, the model generator 204 mayreceive traffic data of the roadway from the traffic monitoring devices109. As discussed elsewhere herein, the traffic data of the roadway maydescribe the traffic on various road segments of the roadway at multipletimestamps. For each road segment of the roadway at each timestamp, thetraffic data of the roadway may include the vehicle density (e.g., 40vehicles/km), the flow rate (e.g., 4000 vehicles/h), the vehicle speed(e.g., 100 km/h), etc., associated with the road segment at thecorresponding timestamp.

In block 504, the model generator 204 may compute one or more trafficmetrics associated with the roadway based on the traffic data of theroadway. The traffic metrics associated with the roadway may indicatevarious properties of the traffic flow on the roadway. In someembodiments, the model generator 204 may determine the roadway capacityindicating the maximum flow rate of the roadway (e.g., 5400vehicles/hour), the capacity vehicle density indicating the vehicledensity of the roadway as the vehicles travel on the roadway with theflow rate equal to the roadway capacity (e.g., 60 vehicles/km), the jamvehicle density indicating the vehicle density of the roadway as thevehicles remain unmoved on the roadway due to traffic congestion (e.g.,180 vehicles/km), etc. Other traffic metrics are also possible andcontemplated.

In block 506, the model generator 204 may compute one or more trafficmetrics associated with the one or more open lanes of the roadway basedon the traffic metrics associated with the roadway and the number ofopen lanes in the mitigation road segment. The traffic metricsassociated with the one or more open lanes may indicate variousproperties of the traffic flow flowing through the one or more openlanes of the roadway. In some embodiments, the traffic metric associatedwith the one or more open lanes may be directly proportional to thenumber of open lanes in the mitigation road segment. As an example, inthe traffic context depicted in FIG. 10A, the roadway 1000 may include 4lanes and the mitigation road segment 1020 may include 1 open lane amongthese 4 lanes (e.g., the lane 1007). In this example, the modelgenerator 204 may determine the roadway capacity of the roadway 1000 tobe 5400 vehicles/hour, and determine the roadway capacity of the one ormore open lanes in the roadway 1000 to be 1350 vehicles/hour (e.g.,5400/4).

In block 508, the model generator 204 may determine one or more roadwayproperties of the roadway. In some embodiments, the roadway propertiesof the roadway may indicate the static properties associated with theroadway (e.g., speed limit, number of lanes, etc.). The model generator204 may also determine roadway properties of the one or more open lanesin the mitigation road segment of the roadway. Similarly, the roadwayproperties of the one or more open lanes may indicate the staticproperties associated with the one or more open lanes (e.g., speedlimit, number of open lanes, etc.). Continuing the example in FIG. 10A,the model generator 204 may determine that the roadway 1010 includes 4lanes with the speed limit of 120 km/h. In this example, the modelgenerator 204 may also determine that the one or more open lanes in themitigation road segment 1020 of the roadway 1010 includes 1 open lanewith the speed limit of 120 km/h. It should be understood that otherroadway properties are also possible and contemplated.

In block 510, the model generator 204 may generate the first trafficdiagram associated with the roadway in the unimpeded traffic conditionbased on an initial traffic diagram, the traffic metrics associated withthe roadway, and the roadway properties of the roadway. In someembodiments, the model generator 204 may retrieve the initial trafficdiagram from the vehicle data store 121. The initial traffic diagram maybe a fundamental diagram for describing a traffic flow with one or morerelationships between the flow rate, the vehicle density, the vehiclespeed, etc., associated with the traffic flow. In some embodiments, themodel generator 204 may adjust one or more diagram parameters,coefficient values, etc., of the initial traffic diagram using thetraffic metrics associated with the roadway (e.g., roadway capacity,capacity vehicle density, jam vehicle density, etc.) and the roadwayproperties of the roadway (e.g., speed limit, number of lanes, etc.),thereby generating the first traffic diagram associated with the roadwayin the unimpeded traffic condition. As discussed elsewhere herein, thefirst traffic diagram associated with the roadway in the unimpededtraffic condition may describe the traffic flow on the roadway as alllanes of the roadway are not impeded. In this present disclosure, thefirst traffic diagram associated with the roadway in the unimpededtraffic condition may be referred to simply as the first trafficdiagram.

In block 512, the model generator 204 may generate the second trafficdiagram associated with the one or more open lanes in the impededtraffic condition based on the initial traffic diagram, the trafficmetrics associated with the one or more open lanes, and the roadwayproperties of the one or more open lanes. Similar to generating thefirst traffic diagram, the model generator 204 may adjust one or morediagram parameters, coefficient values, etc., of the initial trafficdiagram using the traffic metrics associated with the one or more openlanes and the roadway properties of the one or more open lanes, therebygenerating the second traffic diagram associated with the one or moreopen lanes in the impeded traffic condition. As discussed elsewhereherein, the second traffic diagram associated with the one or more openlanes in the impeded traffic condition may describe the traffic flowflowing through the one or more open lanes of the roadway as the controllane and the one or more impedible lanes are impeded while the one ormore open lanes are not impeded in the mitigation road segment of theroadway. In this present disclosure, the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition may be referred to simply as the second traffic diagram.

In block 514, the model generator 204 may generate a traffic modelassociated with the mitigation road segment of the roadway. The trafficmodel may include the first traffic diagram associated with the roadwayin the unimpeded traffic condition and the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition. In some embodiments, the model generator 204 may aggregatethe first traffic diagram and the second traffic diagram in the samecoordinate system to generate the traffic model.

FIG. 9A illustrates an example traffic model 902 associated with themitigation road segment of the roadway. As shown, the traffic model 902may include the first traffic diagram 912 associated with the roadway inthe unimpeded traffic condition and the second traffic diagram 914associated with the one or more open lanes in the impeded trafficcondition. Thus, the first traffic diagram 912 may describe the trafficflow flowing through all lanes of the roadway as all lanes of theroadway are not impeded in the unimpeded traffic condition. The secondtraffic diagram 914 may describe the traffic flow flowing through theone or more open lanes of the roadway as the control lane is impeded bythe first controllable vehicle 103, the one or more impedible lanes 1003are impeded by the proximate controllable vehicle 103, and the one ormore open lanes are not impeded in the unimpeded traffic condition.

As depicted in FIG. 9A, the first traffic diagram 912 and the secondtraffic diagram 914 may describe their corresponding traffic flow withthe relationship between the flow rate q and the vehicle density ρassociated with the corresponding traffic flow. In some embodiments, theflow rate q, the vehicle density ρ, and the vehicle speed v associatedwith a traffic flow may be related to one another by the followingEquation 1:

flow rate q=vehicle density ρ*vehicle speed v   [1]

In some embodiments, once the model generator 204 generates a trafficdiagram indicating the relationship between a pair of factors for thetraffic flow (e.g., the flow rate q and the vehicle density ρ), themodel generator 204 may derive other traffic diagrams indicating therelationship between other pairs of factors for the traffic flow (e.g.,the vehicle speed v and the vehicle density ρ, the vehicle speed v andthe flow rate q, etc.) from that previously generated traffic diagramusing Equation 1. In this present disclosure, the traffic diagram mayrefer to the traffic diagram indicating the relationship between theflow rate q and the vehicle density ρ of the traffic flow, the trafficdiagram indicating the relationship between the vehicle speed v and thevehicle density ρ of the traffic flow, etc. Other types of trafficdiagram are also possible and contemplated.

Referring back to FIG. 4, in block 406, the traffic oscillation analyzer206 may determine a target traffic state for an upstream portion of themitigation road segment, the upstream portion of the mitigation roadsegment may be located upstream of the first controllable vehicle 103 inthe mitigation road segment. FIG. 6 is a flowchart of an example method600 for determining the target traffic state for the upstream portion ofthe mitigation road segment. In some embodiments, the target trafficstate for the upstream portion of the mitigation road segment may bedetermined based on the traffic wave propagating along the roadway.

In block 602, the traffic oscillation analyzer 206 may determine thetraffic wave on the roadway and one or more propagation parameters ofthe traffic wave. The traffic wave on the roadway is usually caused bythe traffic congestion. Non-limiting examples of the traffic waveinclude, but are not limited to, a shockwave, a rarefraction wave, etc.As an example of a traffic wave, when traffic congestion occurs, thevehicles need to stop when they reach the congested area. Thus, thetraffic congestion may cause behind it a traffic stop region in whichthe vehicles cannot move forward due to the traffic congestion, and atraffic moving region in which the vehicles may still move forward. Asthe number of vehicles reaching the congested area from behind isgenerally higher than the number of vehicles leaving the congested areaat the front, the traffic stop region often expands backward as moreupstream vehicles approach the congested area. As a result, the boundaryline between the traffic stop region and the traffic moving region isusually not stationary. Instead, the boundary line between the trafficstop region and the traffic moving region generally travels backward inthe form of a traffic wave (e.g., a shockwave) that propagates along theroadway in the upstream direction opposite to the moving direction ofthe vehicles.

FIG. 7 is a flowchart of an example method 700 for determining thetraffic wave on the roadway and propagation parameters of the trafficwave. In block 702, the traffic oscillation analyzer 206 may receivevehicle movement data of one or more vehicles located on the roadway atmultiple timestamps. In some embodiments, as the controllable vehicles103 and/or the responsive vehicles 107 travel along the roadway, thesevehicles may periodically transmit their vehicle movement data to theserver 101 and/or to other vehicles located within their communicationrange at a predefined interval (e.g., every 2 s, 5 s, 10 s, etc.). Thus,the traffic oscillation analyzer 206 may receive the vehicle movementdata of the controllable vehicles 103 and/or the responsive vehicles 107located on various road segments of the roadway at multiple timestamp.As discussed elsewhere herein, the vehicle movement data of a vehicle ata particular timestamp may include the vehicle location (e.g., GPScoordinates), the vehicle speed, the vehicle lane (e.g., lane number),etc., of the vehicle at the corresponding timestamp. Other types ofvehicle movement data are also possible and contemplated.

In block 704, for each timestamp, the traffic oscillation analyzer 206may determine a vehicle density distribution associated with the roadwayat the corresponding timestamp. The vehicle density distribution maydescribe the vehicle density at various road segments of the roadway atthe corresponding timestamp, and may be determined based on the vehiclemovement data of the vehicles located on the roadway at thecorresponding timestamp and the first traffic diagram associated withthe roadway in the unimpeded traffic condition. As discussed elsewhereherein, the first traffic diagram associated with the roadway in theunimpeded traffic condition may describe the traffic flow on the roadwayin the unimpeded traffic condition with the relationship between thevehicle speed v and the vehicle density ρ associated with the trafficflow.

In some embodiments, to generate the vehicle density distributionassociated with the roadway at the timestamp t=t₁, the trafficoscillation analyzer 206 may analyze the vehicle movement data ofvarious vehicles located on the roadway (e.g., the controllable vehicles103 and/or the responsive vehicles 107), and determine the vehiclelocation, the vehicle speed, the vehicle lane, etc., of these vehiclesat the timestamp t=t₁. For each vehicle among these vehicles, thetraffic oscillation analyzer 206 may determine the road segment of theroadway that includes the vehicle location of the vehicle at thetimestamp t=t₁, and determine the vehicle density ρ of the road segmentat the timestamp t=t₁ based on the vehicle speed v₁ of the vehicletravelling on the road segment at the timestamp t=t₁, and therelationship between the vehicle speed v and the vehicle density ρassociated with the traffic flow on the roadway indicated by the firsttraffic diagram (the first traffic diagram associated with the roadwayin the unimpeded traffic condition in which all lanes are unimpeded). Insome embodiments, if the road segment includes multiple controllablevehicles 103 and/or responsive vehicles 107 at the timestamp t=t₁, thetraffic oscillation analyzer 206 may compute an average vehicle speed ofthese vehicles, and determine the vehicle density ρ₁ of the road segmentat the timestamp t=t₁ using the average vehicle speed of these vehiclesin a similar manner.

In some embodiments, once the vehicle density ρ₁ in various roadsegments of the roadway at the timestamp t=t₁ are determined, thetraffic oscillation analyzer 206 may aggregate the vehicle density ρ₁ ofvarious road segments into the vehicle density distribution associatedwith the roadway at the timestamp t=t₁. In some embodiments, the trafficoscillation analyzer 206 may apply additional processing to smooth thevehicle density distribution associated with the roadway at thetimestamp t=t₁, thereby increasing its accuracy.

In block 706, the traffic oscillation analyzer 206 may determine thetraffic wave on the roadway and one or more propagation parameters ofthe traffic wave. In some embodiments, once the vehicle densitydistribution associated with the roadway at various timestamps t₁ . . .t_(n) are determined, the traffic oscillation analyzer 206 may analyzethe vehicle density distributions associated with the roadway at varioustimestamps, and determine the traffic wave on the roadway based on thesevehicle density distributions. In some embodiments, the trafficoscillation analyzer 206 may also apply a kinematic wave model to thevehicle density distributions associated with the roadway at varioustimestamps to determine the propagation parameters of the traffic wave.In some embodiments, the propagation parameters may describe thepropagation of the traffic wave along the roadway over time.Non-limiting examples of the propagation parameters of the traffic waveinclude, but are not limited to, the propagation speed (e.g., 15 km/h),the propagation distance, the coverage area of the traffic stop regionassociated with the traffic wave, the coverage area of the trafficmoving region associated with the traffic wave, etc. Other propagationparameters of the traffic wave are also possible and contemplated.

Referring back to FIG. 6, in block 604, the traffic oscillation analyzer206 may determine the vehicle density of the mitigation road segment atthe current timestamp t=t_(current). In some embodiments, the trafficoscillation analyzer 206 may determine a vehicle (e.g., a controllablevehicle 103 or a responsive vehicle 107) located in the mitigation roadsegment at the current timestamp t=t_(current). For example, the trafficoscillation analyzer 206 may determine the vehicle location, the vehiclespeed, the vehicle lane, etc., of the vehicle at the current timestampt=t_(current) from the vehicle movement data of the vehicle, anddetermine that the vehicle location of the vehicle at the currenttimestamp t=t_(current) is included in the mitigation road segment. Thetraffic oscillation analyzer 206 may then determine the vehicle densityρ_(current) of the mitigation road segment at the current timestampt=t_(current) based on the vehicle speed of the vehicle at the currenttimestamp t=t_(current), and the relationship between the vehicle speedv and the vehicle density ρ associated with the traffic flow on theroadway indicated by the first traffic diagram (the first trafficdiagram associated with the roadway in the unimpeded traffic conditionin which all lanes are unimpeded). In some embodiments, if themitigation road segment includes multiple controllable vehicles 103and/or responsive vehicles 107 at the timestamp t=t_(current), thetraffic oscillation analyzer 206 may compute an average vehicle speed ofthese vehicles, and determine the vehicle density ρ_(current) of themitigation road segment at the timestamp t=t_(current) using the averagevehicle speed of these vehicles in a similar manner. Continuing theexample in FIG. 10A, the traffic oscillation analyzer 206 may determinethe vehicle density ρ_(current) of the mitigation road segment 1020 atthe current timestamp t=t_(current) to be 40 vehicles/km.

In block 606, the traffic oscillation analyzer 206 may estimate thevehicle density of the mitigation road segment at the future timestampt=t_(future). In some embodiments, the traffic oscillation analyzer 206may determine the future timestamp t=t_(future)=t_(current)+Δ_(t), inwhich Δ_(t) may be a predefined time distance between the currenttimestamp t=t_(current) and the future timestamp t=t_(future) (e.g., 2s, 5 s, 10 s, etc.). In some embodiments, the traffic oscillationanalyzer 206 may estimate the average vehicle density ρ_(future) of themitigation road segment at the future timestamp t=t_(future) based onthe vehicle density ρ_(current) of the mitigation road segment at thecurrent timestamp t=t_(current) and the propagation parameters of thetraffic wave. As discussed elsewhere herein, the propagation parametersof the traffic wave may describe the propagation of the traffic wavealong the roadway over time. Continuing the example in FIG. 10A, thetraffic oscillation analyzer 206 may estimate the average vehicledensity ρ_(future) of the mitigation road segment 1020 at the futuretimestamp t=t_(future)=(t_(current)+2s) to be 60 vehicles/km.

In block 608, the traffic oscillation analyzer 206 may determine thetarget traffic state for the upstream portion of the mitigation roadsegment based on the average vehicle density ρ_(future) of themitigation road segment at the future timestamp t=t_(future). In someembodiments, the target traffic state for the upstream portion of themitigation road segment may be the steady state that has the vehicledensity equal to the average vehicle density ρ_(future) of themitigation road segment at the future timestamp t=t_(future). Thisimplementation is particularly advantageous, because the targetmitigation speed determined based on this target traffic state andapplied to the first controllable vehicle 103 and/or the proximatecontrollable vehicles 103 can transition the upstream portion of themitigation road segment directly to the target traffic state. As thetarget traffic state may have the vehicle density equal to the averagevehicle density ρ_(future) of the mitigation road segment at the futuretimestamp t=t_(future), this implementation can prevent the traffic wavefrom further propagating upstream of the roadway, thereby smoothing thetraffic oscillation for the vehicles located upstream of the mitigationroad segment.

In some embodiments, the traffic oscillation analyzer 206 may determinethe target traffic state for the upstream portion of the mitigation roadsegment on the first traffic diagram associated with the roadway in theunimpeded traffic condition. In particular, the traffic oscillationanalyzer 206 may position the target traffic state for the upstreamportion of the mitigation road segment onto the first traffic diagrambased on the average vehicle density v,v-future of the mitigation roadsegment at the future timestamp t=t_(future). For example, as depictedin FIG. 9A, the traffic oscillation analyzer 206 may position the targettraffic state A for the upstream portion of the mitigation road segmentonto the first traffic diagram 912 associated with the roadway in theunimpeded traffic condition based on the estimated average vehicledensity of the mitigation road segment at the future timestampt=t_(future) (e.g., 60 vehicles/km). tur

Referring back to FIG. 4, in block 408, the target speed calculator 208may determine the target mitigation speed for the first controllablevehicle 103 based on the first traffic diagram associated with theroadway in the unimpeded traffic condition, the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition, and the target traffic state for the upstream portion of themitigation road segment. As discussed elsewhere herein, the targetmitigation speed may be applied to the first controllable vehicle 103 inthe control lane and/or the proximate controllable vehicles 103 in theimpedible lanes of the mitigation road segment.

In some embodiments, to determine the target mitigation speed, thetarget speed calculator 208 may determine a tangent line in the trafficmodel, the tangent line may include the target traffic state on thefirst traffic diagram associated with the roadway in the unimpededtraffic condition and may be tangent to the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition. For example, as depicted in FIG. 9A, the target speedcalculator 208 may determine the tangent line 920, the tangent line 920may include the target traffic state A on the first traffic diagram 912and may be tangent to the second traffic diagram 914. As discussedelsewhere herein, the first traffic diagram 912 may describe the trafficflow flowing through all lanes of the roadway as all lanes of theroadway are not impeded in the unimpeded traffic condition. The secondtraffic diagram 914 may describe the traffic flow flowing through theone or more open lanes of the roadway as the control lane and the one ormore impedible lanes are respectively impeded by the first controllablevehicle 103 and the proximate controllable vehicles 103 while the one ormore open lanes are not impeded in the impeded traffic condition. Thetarget traffic state A may be the target traffic state for the upstreamportion of the mitigation road segment and may have the vehicle densityequal to the average vehicle density of the mitigation road segment atthe future timestamp t=t_(future).

In some embodiments, the target speed calculator 208 may determine aninitiation traffic state of the one or more open lanes on the secondtraffic diagram based on the tangent line. The initiation traffic stateof the one or more open lanes may indicate the traffic state of the oneor more open lanes in the impeded traffic condition at the start pointof mitigation process, and may be used to determine the targetmitigation speed applied to the first controllable vehicle 103 in thecontrol lane and the proximate controllable vehicles 103 in theimpedible lanes to perform the mitigation.

As depicted in FIG. 9A, to determine the initiation traffic state of theone or more open lanes, the target speed calculator 208 may determinethe tangent point 922 at which the tangent line 920 is tangent to thesecond traffic diagram 914 associated with the one or more open lanes inthe impeded traffic condition, and determine the initiation trafficstate B of the one or more open lanes to be the tangent point 922.Alternatively, the target speed calculator 208 may determine a proximaterange B₁B₂ associated with the tangent point 922 on the second trafficdiagram 914, the proximate range B₁B₂ may have a predefined size (e.g.,as indicated by the distance 924) and may include multiple trafficstates on the second traffic diagram 914 that are proximate to thetangent point 922. The target speed calculator 208 may then randomlydetermine the initiation traffic state B of the one or more open lanesfrom the proximate range B₁B₂ on the second traffic diagram 914. Otherimplementations for determining the initiation traffic state of the oneor more open lanes are also possible and contemplated.

In some embodiments, the target speed calculator 208 may determine thestate transition line in the traffic model. As depicted in FIG. 9A, thetarget speed calculator 208 may determine the state transition line ABthat includes the initiation traffic state B of the one or more openlanes located on the second traffic diagram 914 (the second trafficdiagram associated with the one or more open lanes in the impededtraffic condition), and the target traffic state A for the upstreamportion of the mitigation road segment located on the first trafficdiagram 912 (the first traffic diagram associated with the roadway inthe unimpeded traffic condition). As depicted in FIG. 9A, if the targetspeed calculator 208 determines the initiation traffic state B of theone or more open lanes to be the tangent point 922 at which the tangentline 920 is tangent to the second traffic diagram 914, the statetransition line AB and the tangent line 920 may be coincident, and thestate transition line AB may be tangent to the second traffic diagram914 at the initiation traffic state B. On the other hand, if the targetspeed calculator 208 determines the initiation traffic state B of theone or more open lanes from the proximate range B₁B₂ associated with thetangent point 922, the state transition line AB may be substantiallytangent to the second traffic diagram 914.

In some embodiments, the target speed calculator 208 may determine thetarget mitigation speed for the first controllable vehicle 103 and/orthe proximate controllable vehicles 103 based on the state transitionline AB. In particular, the target speed calculator 208 may determinethe target mitigation speed v*₀ being applied to the first controllablevehicle 103 and/or the proximate controllable vehicles 103 to be theslope of the state transition line AB. As depicted in FIG. 9A, the slopeof the state transition line AB may be the tangent of the angle α, andthus the target mitigation speed v*₀ may equal to Tan(α). In someembodiments, the target mitigation speed v*₀ may be lower than the speedlimit of the roadway and generally lower than vehicle speed at which thesurrounding vehicles travel on the roadway.

As discussed above, the state transition line AB may include theinitiation traffic state B of the one or more open lanes in the impededtraffic condition, the initiation traffic state B may indicate thetraffic state of the one or more open lanes as the control lane and theone or more impedible lanes are respectively impeded by the firstcontrollable vehicle 103 and the proximate controllable vehicles 103 atthe start point of the mitigation process. The state transition line ABmay also include the target traffic state A for the upstream portion ofthe mitigation road segment in the unimpeded traffic condition. Thus, asthe first controllable vehicle 103 and the proximate controllablevehicles 103 travel at the target mitigation speed v*₀ equal to theslope of the state transition line AB in their corresponding lane, theinitiation traffic state B may be transitioned to achieve the targettraffic state A. As a result, the upstream portion of the mitigationroad segment may be transitioned to the target traffic state A. Asdiscussed elsewhere herein, the target traffic state A may have thevehicle density equal to the average vehicle density of the mitigationroad segment 1020 at the future timestamp t=t_(future). Thus, as theupstream portion of the mitigation road segment 1020 is transitioned tothe target traffic state A, the traffic wave may be prevented fromfurther propagating upstream of the roadway.

Additionally, if the mitigation road segment includes a single (e.g.,only one) open lane, as the first controllable vehicle 103 and theproximate controllable vehicles 103 travel at the target mitigationspeed v*₀ equal to the slope of the state transition line AB in theircorresponding lane, the passing flow rate at which the traffic streamflowing through the only open lane passes the first controllable vehicle103 and/or the proximate controllable vehicles 103 travelling in theircorresponding lane may be maximized, given the target traffic state Athat needs to be achieved. If the mitigation road segment includesmultiple open lanes, as the first controllable vehicle 103 and theproximate controllable vehicles 103 travel at the target mitigationspeed v*₀ equal to the slope of the state transition line AB in theircorresponding lane, the overall passing flow rate at which the trafficflow flowing through the multiple open lanes passes the firstcontrollable vehicle 103 and/or the proximate controllable vehicles 103travelling in their corresponding lane may be maximized, given thetarget traffic state A that needs to be achieved. This advantageouseffect is described in detail below with reference to FIG. 9B.

FIG. 9B illustrates an example vehicle passing model 904 associated withthe mitigation road segment of the roadway, the vehicle passing model904 may be generated based on the traffic model 902 associated with themitigation road segment of the roadway. As discussed elsewhere herein,the traffic model 902 may include the traffic diagrams describing therelationship between the flow rate q and the vehicle density ρ ofvarious traffic flows, each traffic flow may flow through one or moreparticular lanes in a particular traffic condition. For example, thesecond traffic diagram 914 in the traffic model 902 may describe therelationship between the flow rate q and the vehicle density ρ of thetraffic flow flowing through one or more open lanes of the roadway inthe impeded traffic condition. In some embodiments, the vehicle passingmodel 904 may include the corresponding passing diagrams that describethe relationship between the passing flow rate q* and the vehicledensity ρ of these traffic flows.

In some embodiments, the flow rate q of the traffic flow flowing throughthe particular lane(s) may indicate the number of vehicles travelling inthese particular lane(s) that pass a static point of observation in apredefined time period. On the other hand, the passing flow rate q* ofthe same traffic flow may indicate the number of vehicles travelling inthese particular lane(s) that pass a dynamic point of observation as thedynamic point of observation travels at the observer speed v₀. In someembodiments, the flow rate q and the passing flow rate q* of the sametraffic flow may be related to one another by the following Equation 2:

passing flow rate q*=flow rate q−observer speed v₀*vehicle densityρ  [2]

Thus, in some embodiments, the model generator 204 may derive thepassing diagrams of the vehicle passing model 904 from the correspondingtraffic diagrams of the traffic model 902 using the Equation 2 and theobserver speed v₀ of the dynamic point of observation. An example of thedynamic point of observation may be the first controllable vehicle 103and/or the proximate controllable vehicles 103 travelling in theircorresponding lane at the vehicle speed v=v₀.

According to Equation 2, if the first controllable vehicle 103 and theproximate controllable vehicles 103 travel in their corresponding laneat the vehicle speed v=0, the observer speed v₀=0 and the passing flowrate q*=the flow rate q. Therefore, as depicted in FIG. 9B, the modelgenerator 204 may consider the first traffic diagram 912 and the secondtraffic diagram 914 in the traffic model 902 to be the correspondingpassing diagrams in the vehicle passing model 904 for the scenario inwhich the first controllable vehicle 103 and the proximate controllablevehicles 103 travel in their corresponding lane at the vehicle speedv=0. In some embodiments, if the first controllable vehicle 103 and theproximate controllable vehicles 103 travel in their corresponding laneat the target mitigation speed v*₀, the observer speed v₀=the targetmitigation speed v*₀=Tan(α). As depicted in FIG. 9B, the model generator204 may generate the first passing diagram 932 corresponding to thefirst traffic diagram 912 and generate the second passing diagram 934corresponding to the second traffic diagram 914 for the scenario inwhich the first controllable vehicle 103 and the proximate controllablevehicles 103 travel in their corresponding lane at the target mitigationspeed v*₀=Tan(α). According to Equation 2, the first passing diagram 932may be related to the first traffic diagram 912 and the second passingdiagram 934 may be related to the second traffic diagram 914 by thefollowing Equation 3:

q*=q−Tan(α)* ρ  [3]

According to Equation 3, the passing flow rate q*_(B) corresponding tothe initiation traffic state B and the passing flow rateq*_(A)corresponding to the target traffic state A may be determined asfollows:

q* _(B) =q _(B)−Tan(α)* ρ_(B) =BB ₂−-BB ₁ =B ₁ B ₂ =q* ₀   [4]

q* _(A) =q _(A)−Tan(α)*ρ_(A) =AA ₂ −AA ₁ =A1A ₂ =q* ₀   [5]

As indicated in Expression 4, q*_(B)=B₁B₂, and thus the initiationtraffic state B located on the second traffic diagram 914 may becorresponding to the initiation traffic state B₁ located on secondpassing diagram 934 for the scenario in which the first controllablevehicle 103 and the proximate controllable vehicles 103 travel in theircorresponding lane at the target mitigation speed v*₀. Similarly, asindicated in Expression 5, q*_(A)=A₁A₂, and thus the target trafficstate A located on the first traffic diagram 912 may be corresponding tothe target traffic state A₁ located on the first passing diagram 932 forthe scenario in which the first controllable vehicle 103 and theproximate controllable vehicles 103 travel in their corresponding laneat the target mitigation speed v*₀.

As indicated in Expression 4 and Expression 5, the initiation trafficstate B₁ located on second passing diagram 934 and the target trafficstate A₁ located on the first passing diagram 932 may have the samepassing flow rate q*_(B)=q*₀ and q*_(A)*=q*₀, due to the statetransition line AB being tangent to the second traffic diagram 914 atthe initiation traffic state B and the target mitigation speed v*₀applied to the first controllable vehicle 103 and the proximatecontrollable vehicles 103 being equal to the slope of the statetransition line AB (e.g., Tan(α)) as depicted in FIG. 9B. Thus, theinitiation traffic state B₁ located on second passing diagram 934 andthe target traffic state A₁ located on the first passing diagram 932 maybelong to the same horizontal line corresponding to the passing flowrate q*=q*₀ as depicted in FIG. 9B.

In some embodiments, if the mitigation road segment includes a singleopen lane, the initiation traffic state B₁ may indicate the passing flowrate at which the traffic stream flowing through the only open lanepasses the first controllable vehicle 103 and/or the proximatecontrollable vehicles 103 travelling in their corresponding lane at thetarget mitigation speed v*₀. If the mitigation road segment includesmultiple open lanes, the initiation traffic state B₁ may indicate theoverall passing flow rate at which the traffic flow flowing through themultiple open lane passes the first controllable vehicle 103 and/or theproximate controllable vehicles 103 travelling in their correspondinglane at the target mitigation speed v*₀. Thus, as the initiation trafficstate B₁ located on second passing diagram 934 and the target trafficstate A₁ located on the first passing diagram 932 belong to the samehorizontal line corresponding to the passing flow rate q*=q*₀ asdepicted in FIG. 9B, the passing flow rate or the overall passing flowrate indicated by the initiation traffic state B i can be maximized,given the target traffic state A₁ corresponding to the target trafficstate A that needs to be achieved. Accordingly, as the firstcontrollable vehicle 103 and/or the proximate controllable vehicles 103travel in their corresponding lane at the target mitigation speed v*₀,these controllable vehicles 103 may impede the traffic stream in theircorresponding lane to maximize the number of vehicles passing themthrough the one or more open lanes as allowed by the target trafficstate A that needs to be achieved.

As depicted in FIG. 9B, the target speed calculator 208 may determinethe initiation traffic state B to be the tangent point 922 of thetangent line 920, and thus the state transition line AB may be tangentto the second traffic diagram 914 at the initiation traffic state B inthe vehicle passing model 904. As discussed above, this implementationmay result in the passing flow rate or the overall passing flow rate ofthe traffic flow flowing through the one or more open lanes as indicatedby the initiation traffic state B₁ being maximized. As discussedelsewhere herein, the target speed calculator 208 may determine theinitiation traffic state B from the proximate range B₁B₂ associated withthe tangent point 922, and thus the state transition line AB may besubstantially tangent to the second traffic diagram 914. While thisimplementation may not maximize the passing flow rate/overall passingflow rate of the traffic flow flowing through the one or more openlanes, it may increase the passing flow rate/overall passing flow rateto a value approximate to the maximal value of the passing flowrate/overall passing flow rate given the target traffic state A (e.g.,the difference between these two values may satisfy a thresholddifference, depending on the predefined size of the proximate rangeB₁B₂).

In some embodiments, the target speed calculator 208 may determine theintersection between the state transition line A₁B₁ corresponding to thestate transition line AB and the first passing diagram 932 to be theresult traffic state C. Accordingly, as the first controllable vehicle103 and/or the proximate controllable vehicles 103 travel in theircorresponding lane at the target mitigation speed v*₀, the upstreamportion of the mitigation road segment may be transition to the targettraffic state A₁ corresponding to the target traffic state A, and theroad segment located downstream of the mitigation road segment butupstream of the traffic congestion (also referred to herein simply asthe downstream road segment) may be transition to the result trafficstate C. As indicated on the first passing diagram 932, the resulttraffic state C achieved in the downstream road segment may have thesame passing flow rate/overall passing flow rate q*₀ but have a lowervehicle density ρ as compared to the target traffic state A₁ achieved inthe upstream portion of the mitigation road segment. Thus, the resulttraffic state C achieved in the downstream road segment may result in aforward shockwave in which a traffic region with a lower vehicle densityρ as compared to the upstream portion of the mitigation road segment maypropagate forward along the roadway towards the traffic congestion, andthus the traffic congestion can be mitigated.

FIG. 10B illustrates an example 1002 of the adjusted traffic streams onthe roadway 1010 to mitigate the traffic congestion situation 1000depicted in FIG. 10A. As discussed elsewhere herein, in this example,the target mitigation speed v*₀ may be applied to the first controllablevehicle C1050 travelling in the control lane 1005, the proximatecontrollable vehicle C1030 travelling in the impedible lane 1003, theproximate controllable vehicle C1090 travelling in the impedible lane1009 in the mitigation road segment 1020. As discussed elsewhere herein,the target mitigation speed v*₀ may be lower than the speed limit of theroadway 1010 (e.g., 120 km/h) and generally lower than the vehicle speedof other vehicles surrounding the controllable vehicles C1050, C1030,C1090. As a result, the first controllable vehicle C1050, the proximatecontrollable vehicle C1030, the proximate controllable vehicle C1090 mayrespectively impede the traffic stream in the control lane 1005, theimpedible lane 1003, the impedible lane 1009 as they travel in theircorresponding lane at the target mitigation speed v*₀.

In this example, because the traffic streams in the control lane 1005,the impedible lane 1003, the impedible lane 1009 are impeded, othervehicles travelling behind the first controllable vehicle C1050, theproximate controllable vehicle C1030, the proximate controllable vehicleC1090 in the control lane 1005, the impedible lane 1003, the impediblelane 1009 may likely perform one or more lane change maneuvers when itis possible to shift to the open lane 1007 for faster movement asindicated by the lane-change streams 1040. As discussed elsewhereherein, the target mitigation speed v*₀ applied to the controllablevehicles C1050, C1030, C1090 may maximize the passing flow rate (orincrease the passing flow rate to a value approximate to the maximalvalue of the passing flow rate) at which the traffic stream flowingthrough the open lane 1007 passes the controllable vehicles C1050,C1030, C1090, given the target traffic state to be achieved in theupstream portion of the mitigation road segment 1020. Thus, thecontrollable vehicles C1050, C1030, C1090 may impede the traffic streamsin their corresponding lane to limit the upstream traffic headingtowards the congested area 1012, while still allow a portion of thisupstream traffic that can be accommodated by the downstream road segment1022 to proceed forward through the open lane 1007 to achieve the targettraffic state in the upstream portion of the mitigation road segment1020.

As depicted in FIG. 10B, once the vehicles travelling in the open lane1007 pass the controllable vehicles C1050, C1030, and C1090, thesevehicles may perform one or more lane change maneuvers when it ispossible to shift from the open lane 1007 to other lanes in thedownstream road segment 1022 as indicated by the lane-change streams1042. As the traffic streams in the control lane 1005, the impediblelane 1003, the impedible lane 1009 are impeded, and only a limitedportion of the upstream traffic can reach the downstream road segment1022 through the open lane 1007, the downstream road segment 1022 mayhave a lower vehicle density ρ as compared to the upstream portion ofthe mitigation road segment 1020. Thus, as the traffic approaching thecongested area 1012 from behind has a reduced vehicle density ρ and somevehicles may leave the congested area 1012 at the front, the trafficcongestion in the congested area 1012 can be mitigated and eventuallyfully addressed.

Additionally, as discussed above, the controllable vehicles C1050,C1030, C1090 travelling at the target mitigation speed v*₀ may allow aportion of the upstream traffic to proceed forward through the open lane1007 to achieve the target traffic state in the upstream portion of themitigation road segment 1020. As discussed elsewhere herein, the targettraffic state may be the steady state that has the vehicle density equalto the average vehicle density of the mitigation road segment at thefuture timestamp. As the target traffic state having the vehicle densityequal to the average vehicle density of the mitigation road segment atthe future timestamp is achieved in the upstream portion of themitigation road segment 1020, the traffic wave caused by the trafficcongestion may be prevented from further propagating upstream of theroadway 1010. Thus, the target mitigation speed v*₀ determined by thetraffic mitigation application 120 when applied to the controllablevehicles C1050, C1030, C1090 can resolve the traffic congestion locateddownstream of the mitigation road segment 1020, and also can prevent thevehicles located upstream of the mitigation road segment 1020 from beingaffected by the traffic oscillation caused by the propagation of thetraffic wave.

In some embodiments, once the target speed calculator 208 determines thetarget mitigation speed v₀ (e.g., 70 km/h), to apply the targetmitigation speed v*₀ to the first controllable vehicle 103 in thecontrol lane and the proximate controllable vehicles 103 in the one ormore impedible lanes, the traffic mitigation application 120 may providea traffic mitigating instruction including the target mitigation speedv*₀ to the first controllable vehicle 103 and the proximate controllablevehicles 103. In some embodiments, the traffic mitigation application120 may generate and display a guidance message including the targetmitigation speed v*₀ to the drivers via one or more output devices ofthese controllable vehicles 103. For example, on a touch screen of thefirst controllable vehicle 103, the traffic mitigation application 120may display a dynamic graphical map representing the vehicle location ofthe first controllable vehicle 103 and the traffic congestion on theroadway together with the guidance message (e.g., “Please adjust yourvehicle speed to 70 km/h to help mitigating the traffic congestion andsmooth the traffic oscillation”). Alternatively, the guidance messagemay be provided in the form of a voice instruction for the driver of thefirst controllable vehicle 103 to follow and adjust the vehicle speed ofthe first controllable vehicle 103 accordingly.

In some embodiments, the traffic mitigation application 120 maycommunicate the target mitigation speed v*₀ (e.g., 70 km/h) to thecontrol unit (e.g., the ECU) of the first controllable vehicle 103 andthe proximate controllable vehicles 103. The control unit may actuatethe speed actuators of these controllable vehicles 103 to adjust thevehicle speed of these controllable vehicles 103 to the targetmitigation speed v*₀. As a result, the first controllable vehicle 103and the proximate controllable vehicles 103 may automatically adapttheir vehicle speed to the target mitigation speed v*₀, therebymitigating the traffic congestion and the traffic oscillation on theroadway.

As discussed above, the traffic mitigation application 120 may apply thetarget mitigation speed v*₀ to both the first controllable vehicle 103and the proximate controllable vehicle 103 in the mitigation roadsegment. From the perspective of the first controllable vehicle 103 orthe proximate controllable vehicle 103 in the mitigation road segment,the mitigation road segment may include the same number of control lane,impedible lanes, and open lanes due to the same set of controllablevehicles 103 located proximate to one another in the mitigation roadsegment. As a result, the traffic model 902 generated for the firstcontrollable vehicle 103 and for each proximate controllable vehicle 103(which includes the first traffic diagram 912 associated with theroadway in the unimpeded traffic condition and the second trafficdiagram 914 associated with the one or more open lanes in the impededtraffic condition) may be identical to one another, and thus the targetmitigation speed v*₀ determined for the first controllable vehicle 103and for the proximate controllable vehicles 103 may have the same value.In some embodiments, the traffic mitigation application 120 maydetermine the target mitigation speed v*₀ for the first controllablevehicle 103, and then apply the target mitigation speed v*₀ to both thefirst controllable vehicle 103 and the proximate controllable vehicles103 in the mitigation road segment.

In some embodiments, to expedite the mitigation of traffic congestionand/or traffic oscillations on the roadway, the traffic mitigationapplication 120 may delay controlling the vehicle speed of the firstcontrollable vehicle 103 until there are proximate controllablevehicle(s) 103 located proximate to the first controllable vehicle 103in the mitigation road segment. This implementation is discussed indetail below with reference to FIG. 8. However, it should be understoodthat the traffic mitigation application 120 is capable of mitigating thetraffic congestion and/or the traffic oscillations using a singlecontrollable vehicle 103 with the embodiments discussed above.

FIG. 8 is a flowchart of an example method 800 for addressing trafficcongestion and mitigating traffic oscillations. In block 802, thetraffic mitigation initiator 202 may determine a first controllablevehicle 103 and a second controllable vehicle 103 traveling along amitigation road segment of a roadway. In some embodiments, the trafficmitigation initiator 202 may determine the first controllable vehicle103 and the mitigation road segment in a manner similar to determiningthe first controllable vehicle 103 traveling along the mitigation roadsegment as discussed above with reference to FIG. 3. The mitigationinitiator 202 may then determine other controllable vehicles 103travelling along the mitigation road segment, and determine that thedistance between the first controllable vehicle 103 and the othercontrollable vehicles 103 does not satisfy the proximity distancethreshold (e.g., less than 5 m). Thus, the mitigation initiator 202 maydetermine that there is no proximate controllable vehicle 103 currentlylocated proximate to the first controllable vehicle 103 in themitigation road segment.

In some embodiments, to determine the second controllable vehicle 103,the mitigation initiator 202 may determine the candidate controllablevehicles 103 travelling along the mitigation road segment that have thedistance between the candidate controllable vehicle 103 and the firstcontrollable vehicle 103 satisfying an initial vehicle distancethreshold (e.g., more than 5 m and less than 20 m), and randomly selectthe second controllable vehicle 103 from these candidate controllablevehicles 103. In some embodiments, the mitigation initiator 202 mayselect among these candidate controllable vehicles 103 the candidatecontrollable vehicle 103 that has the lowest distance between thecandidate controllable vehicle 103 and the first controllable vehicle103 to be the second controllable vehicle 103. In some embodiments, ifthe mitigation initiator 202 determines that the distance between thefirst controllable vehicle 103 and other controllable vehicles 103travelling on the mitigation road segment does not satisfy the initialvehicle distance threshold, the mitigation initiator 202 may determinethat these controllable vehicles 103 are located far away from oneanother. In that situation, the traffic mitigation application 120 maycontrol the vehicle speed of these controllable vehicles 103individually to mitigate the traffic congestion and the trafficoscillation on the roadway.

In block 804, the traffic mitigation initiator 202 may monitor thedistance between the first controllable vehicle 103 and the secondcontrollable vehicle 103. In block 806, the traffic mitigation initiator202 may determine whether the distance between the first controllablevehicle 103 and the second controllable vehicle 103 satisfies theproximity distance threshold (e.g., less than 5 m) at the currenttimestamp t=t_(current). If the distance between the first controllablevehicle 103 and the second controllable vehicle 103 does not satisfy theproximity distance threshold at the current timestamp, the method 800proceeds to block 804 to continue monitoring the distance between thefirst controllable vehicle 103 and the second controllable vehicle 103.If the distance between the first controllable vehicle 103 and thesecond controllable vehicle 103 satisfies the proximity distancethreshold at the current timestamp, the traffic mitigation initiator 202may determine the second controllable vehicle 103 to be the proximatecontrollable vehicle 103 associated with the first controllable vehicle103. The method 800 may then proceed to block 806 to start themitigation process. In some embodiments, the traffic mitigationinitiator 202 may determine multiple second controllable vehicles 103and the traffic mitigation application 120 may start the mitigationprocess when the first controllable vehicle 103 and these secondcontrollable vehicles 103 located proximate to one another.

In some embodiments, the traffic mitigation application 120 may performthe mitigation process with the first controllable vehicle 103 and thesecond controllable vehicle(s) 103 as the proximate controllablevehicle(s) 103. This mitigation process may be performed in a mannersimilar to the mitigation process discussed above with reference toFIGS. 3-7. For example, in block 808, the traffic mitigation initiator202 may determine the control lane and the impedible lane(s) in themitigation road segment. The control lane may include the firstcontrollable vehicle 103 and may be impedible by the first controllablevehicle 103. The impedible lane(s) may include the second controllablevehicle(s) 103 and may be impedible by the second controllablevehicle(s) 103. In block 810, the traffic mitigation initiator 202 maydetermine one or more open lanes in the mitigation road segment. In anexample, the one or more open lanes may be adjacent (e.g., directlyadjacent or indirectly adjacent) to the control lane. In someembodiments, the one or more open lanes may exclude the firstcontrollable vehicle 103 and the second controllable vehicle(s) 103, andthus the traffic flow flowing through the one or more open lanes may notbe impeded.

In block 812, the traffic mitigation application 120 may apply thetarget mitigation speed to the first controllable vehicle 103 in thecontrol lane and the second controllable vehicle(s) 103 in the impediblelane(s). As discussed elsewhere herein, the model generator 204, thetraffic oscillation analyzer 206, and the target speed calculator 208may determine the target mitigation speed for the first controllablevehicle 103 based on the traffic state of the one or more open lanes(e.g., the initiation traffic state B) and the target traffic state forthe upstream portion of the mitigation road segment (e.g., the targettraffic state A). If the mitigation road segment includes a single openlane, the target mitigation speed applied to the first controllablevehicle 103 in the control lane and the second controllable vehicle(s)103 in the impedible lane(s) may adjust the traffic stream flowingthrough the only open lane of the mitigation road segment to mitigatethe traffic congestion and smooth the traffic oscillation. If themitigation road segment includes multiple open lanes, the targetmitigation speed applied to the first controllable vehicle 103 in thecontrol lane and the second controllable vehicle(s) 103 in the impediblelane(s) may adjust the traffic flow flowing through the multiple openlanes of the mitigation road segment to mitigate the traffic congestionand smooth the traffic oscillation.

Thus, as discussed above, the traffic mitigation application 120 maydelay controlling the vehicle speed of the controllable vehicles 103 inthe mitigation road segment until there are multiple controllablevehicle(s) 103 located proximate to one another to simultaneously impedemultiple lanes in the mitigation road segment by these controllablevehicles 103. This implementation is particularly advantageous becauseit can expedite the mitigation of the traffic congestion and the trafficoscillation on the roadway. In particular, as multiple lanes in themitigation road segment are simultaneously impeded by multiplecontrollable vehicles 103, the number of open lanes in the mitigationroad segment may be limited, and thus the flow rate of the traffic flowflowing through these open lanes may be reduced. As discussed elsewhereherein, the flow rate of the traffic flow flowing through the open lanesmay be indicated by the second traffic diagram 914 in FIG. 9A. As theflow rate of the traffic flow flowing through the open lanes is reduced,the slope of the state transition line AB may increase and thus, thetarget mitigation speed v*₀ may also increase. As a result, the firstcontrollable vehicle 103 and the second controllable vehicle(s) 103 towhich the target mitigation speed v*₀ is applied may proceed forwardwith higher vehicle speed during the mitigation process, therebyreducing the amount of time needed to mitigate the traffic congestionand the traffic oscillation.

In the above description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofthe present disclosure. However, it should be understood that thetechnology described herein could be practiced without these specificdetails. Further, various systems, devices, and structures are shown inblock diagram form in order to avoid obscuring the description. Forinstance, various implementations are described as having particularhardware, software, and user interfaces. However, the present disclosureapplies to any type of computing device that can receive data andcommands, and to any peripheral devices providing services.

In some instances, various implementations may be presented herein interms of algorithms and symbolic representations of operations on databits within a computer memory. An algorithm is here, and generally,conceived to be a self-consistent set of operations leading to a desiredresult. The operations are those requiring physical manipulations ofphysical quantities. Usually, though not necessarily, these quantitiestake the form of electrical or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the following discussion,it is appreciated that throughout this disclosure, discussions utilizingterms including “processing,” “computing,” “calculating,” “determining,”“displaying,” or the like, refer to the action and processes of acomputer system, or similar electronic computing device, thatmanipulates and transforms data represented as physical (electronic)quantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission or display devices.

Various implementations described herein may relate to an apparatus forperforming the operations herein. This apparatus may be speciallyconstructed for the required purposes, or it may comprise ageneral-purpose computer selectively activated or reconfigured by acomputer program stored in the computer. Such a computer program may bestored in a computer readable storage medium, including, but is notlimited to, any type of disk including floppy disks, optical disks, CDROMs, and magnetic disks, read-only memories (ROMs), random accessmemories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, flashmemories including USB keys with non-volatile memory or any type ofmedia suitable for storing electronic instructions, each coupled to acomputer system bus.

The technology described herein can take the form of an entirelyhardware implementation, an entirely software implementation, orimplementations containing both hardware and software elements. Forinstance, the technology may be implemented in software, which includesbut is not limited to firmware, resident software, microcode, etc.Furthermore, the technology can take the form of a computer programproduct accessible from a computer-usable or computer-readable mediumproviding program code for use by or in connection with a computer orany instruction execution system. For the purposes of this description,a computer-usable or computer readable medium can be any non-transitorystorage apparatus that can contain, store, communicate, propagate, ortransport the program for use by or in connection with the instructionexecution system, apparatus, or device.

A data processing system suitable for storing and/or executing programcode may include at least one processor coupled directly or indirectlyto memory elements through a system bus. The memory elements can includelocal memory employed during actual execution of the program code, bulkstorage, and cache memories that provide temporary storage of at leastsome program code in order to reduce the number of times code must beretrieved from bulk storage during execution. Input/output or I/Odevices (including but not limited to keyboards, displays, pointingdevices, etc.) can be coupled to the system either directly or throughintervening vIv/0 controllers.

Network adapters may also be coupled to the system to enable the dataprocessing system to become coupled to other data processing systems,storage devices, remote printers, etc., through intervening privateand/or public networks. Wireless (e.g., Wi-Fi™) transceivers, Ethernetadapters, and modems, are just a few examples of network adapters. Theprivate and public networks may have any number of configurations and/ortopologies. Data may be transmitted between these devices via thenetworks using a variety of different communication protocols including,for example, various Internet layer, transport layer, or applicationlayer protocols. For example, data may be transmitted via the networksusing transmission control protocol/Internet protocol (TCP/IP), userdatagram protocol (UDP), transmission control protocol (TCP), hypertexttransfer protocol (HTTP), secure hypertext transfer protocol (HTTPS),dynamic adaptive streaming over HTTP (DASH), real-time streamingprotocol (RTSP), real-time transport protocol (RTP) and the real-timetransport control protocol (RTCP), voice over Internet protocol (VOIP),file transfer protocol (FTP), WebSocket (WS), wireless access protocol(WAP), various messaging protocols (SMS, MMS, XMS, IMAP, SMTP, POP,WebDAV, etc.), or other known protocols.

Finally, the structure, algorithms, and/or interfaces presented hereinare not inherently related to any particular computer or otherapparatus. Various general-purpose systems may be used with programs inaccordance with the teachings herein, or it may prove convenient toconstruct more specialized apparatus to perform the required methodblocks. The required structure for a variety of these systems willappear from the description above. In addition, the specification is notdescribed with reference to any particular programming language. It willbe appreciated that a variety of programming languages may be used toimplement the teachings of the specification as described herein.

The foregoing description has been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the specification to the precise form disclosed. Manymodifications and variations are possible in light of the aboveteaching. It is intended that the scope of the disclosure be limited notby this detailed description, but rather by the claims of thisapplication. As will be understood by those familiar with the art, thespecification may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. Likewise, theparticular naming and division of the modules, routines, features,attributes, methodologies and other aspects are not mandatory orsignificant, and the mechanisms that implement the specification or itsfeatures may have different names, divisions and/or formats.

Furthermore, the modules, routines, features, attributes, methodologiesand other aspects of the disclosure can be implemented as software,hardware, firmware, or any combination of the foregoing. Also, wherevera component, an example of which is a module, of the specification isimplemented as software, the component can be implemented as astandalone program, as part of a larger program, as a plurality ofseparate programs, as a statically or dynamically linked library, as akernel loadable module, as a device driver, and/or in every and anyother way known now or in the future. Additionally, the disclosure is inno way limited to implementation in any specific programming language,or for any specific operating system or environment.

What is claimed is:
 1. A method comprising: determining a firstcontrollable vehicle traveling along a mitigation road segment of aroadway; determining a control lane in the mitigation road segment, thecontrol lane including the first controllable vehicle and beingimpedible by the first controllable vehicle; determining a first openlane in the mitigation road segment, the first open lane being adjacentto the control lane in the mitigation road segment; and applying atarget mitigation speed to the first controllable vehicle in the controllane, the target mitigation speed being based on a traffic state of thefirst open lane, the target mitigation speed adjusting a traffic streamthat flows through the first open lane to mitigate traffic congestionlocated downstream of the mitigation road segment.
 2. The method ofclaim 1, wherein the target mitigation speed increases a passing flowrate at which the traffic stream flowing through the first open lanepasses the first controllable vehicle travelling at the targetmitigation speed in the control lane.
 3. The method of claim 1, furthercomprising: determining a second open lane in the mitigation roadsegment; and wherein the target mitigation speed maximizes an overallpassing flow rate at which the traffic stream flowing through the firstopen lane and a traffic stream flowing through the second open lane passthe first controllable vehicle travelling at the target mitigation speedin the control lane.
 4. The method of claim 1, wherein determining thefirst open lane in the mitigation road segment includes: determining oneor more proximate controllable vehicles located proximate to the firstcontrollable vehicle in the mitigation road segment; and determining thefirst open lane in the mitigation road segment, the first open laneexcluding the one or more proximate controllable vehicles and beingunimpedible by the one or more proximate controllable vehicles.
 5. Themethod of claim 1, further comprising: determining a proximatecontrollable vehicle located proximate to the first controllable vehiclein the mitigation road segment; determining an impedible lane in themitigation road segment, the impedible lane including the proximatecontrollable vehicle and being impedible by the proximate controllablevehicle; and applying the target mitigation speed to the proximatecontrollable vehicle in the impedible lane.
 6. The method of claim 1,further comprising: determining one or more open lanes and one or moreimpedible lanes in the mitigation road segment, the one or more openlanes including the first open lane; generating a first traffic diagramassociated with the roadway in an unimpeded traffic condition, thecontrol lane and the one or more impedible lanes in the mitigation roadsegment being unimpeded in the unimpeded traffic condition; generating asecond traffic diagram associated with the one or more open lanes in animpeded traffic condition, the control lane and the one or moreimpedible lanes in the mitigation road segment being impeded in theimpeded traffic condition; determining a target traffic state for anupstream portion of the mitigation road segment, the upstream portion ofthe mitigation road segment being located upstream of the firstcontrollable vehicle; and determining the target mitigation speed forthe first controllable vehicle based on the first traffic diagramassociated with the roadway in the unimpeded traffic condition, thesecond traffic diagram associated with the one or more open lanes in theimpeded traffic condition, and the target traffic state for the upstreamportion of the mitigation road segment.
 7. The method of claim 6,wherein generating the first traffic diagram associated with the roadwayin the unimpeded traffic condition includes: monitoring traffic data ofthe roadway; computing one or more traffic metrics associated with theroadway based on the traffic data of the roadway; determining one ormore roadway properties of the roadway; generating the first trafficdiagram associated with the roadway in the unimpeded traffic conditionbased on an initial traffic diagram, the one or more traffic metricsassociated with the roadway, and the one or more roadway properties ofthe roadway; and wherein the first traffic diagram indicates arelationship between a flow rate and a vehicle density on the roadway ora relationship between a vehicle speed and the vehicle density on theroadway in the unimpeded traffic condition.
 8. The method of claim 7,wherein the traffic data of the roadway includes one or more of a flowrate, a vehicle density, and a vehicle speed associated with a pluralityof road segments of the roadway at a plurality of timestamps; the one ormore traffic metrics associated with the roadway includes one or more ofa roadway capacity, a capacity vehicle density corresponding to theroadway capacity, and a jam vehicle density associated with the roadway;and the one or more roadway properties of the roadway includes one ormore of a speed limit and a number of lanes associated with the roadway.9. The method of claim 6, wherein generating the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition includes: monitoring traffic data of the roadway; computingone or more traffic metrics associated with the roadway based on thetraffic data of the roadway; computing one or more traffic metricsassociated with the one or more open lanes based on the traffic metricsassociated with the roadway and a number of open lanes in the mitigationroad segment; determining one or more roadway properties of the one ormore open lanes; generating the second traffic diagram associated withthe one or more open lanes in the impeded traffic condition based on aninitial traffic diagram, the one or more traffic metrics associated withthe one or more open lanes, and the one or more roadway properties ofthe one or more open lanes; and wherein the second traffic diagramindicates a relationship between a flow rate and a vehicle density inthe one or more open lanes or a relationship between a vehicle speed andthe vehicle density in the one or more open lanes in the impeded trafficcondition.
 10. The method of claim 6, wherein determining the targettraffic state for the upstream portion of the mitigation road segmentincludes: determining a traffic wave on the roadway and one or morepropagation parameters of the traffic wave; determining a vehicledensity of the mitigation road segment at a current timestamp;estimating an average vehicle density of the mitigation road segment ata future timestamp based on the vehicle density of the mitigation roadsegment at the current timestamp and the one or more propagationparameters of the traffic wave; and determining the target traffic statefor the upstream portion of the mitigation road segment based on theaverage vehicle density of the mitigation road segment at the futuretimestamp.
 11. The method of claim 10, wherein determining the trafficwave on the roadway and the one or more propagation parameters of thetraffic wave includes: receiving vehicle movement data of one or morevehicles located on the roadway at a plurality of timestamps;determining a plurality of vehicle density distributions associated withthe roadway at the plurality of timestamps based on the vehicle movementdata of the one or more vehicles located on the roadway at the pluralityof timestamps and the first traffic diagram associated with the roadwayin the unimpeded traffic condition; and determining the traffic wave onthe roadway and the one or more propagation parameters of the trafficwave based on the plurality of vehicle density distributions associatedwith the roadway at the plurality of timestamps.
 12. The method of claim11, wherein the vehicle movement data of the one or more vehicleslocated on the roadway at the plurality of timestamps includes one ormore of a vehicle location, a vehicle speed, and a vehicle lane of avehicle among the one or more vehicles at a corresponding timestampamong the plurality of timestamps; and the one or more propagationparameters of the traffic wave includes one or more of a propagationspeed, a propagation distance, a coverage area of a traffic stop regionassociated with the traffic wave, and a coverage area of a trafficmoving region associated with the traffic wave.
 13. The method of claim10, wherein determining the vehicle density of the mitigation roadsegment at the current timestamp includes: receiving vehicle movementdata of a vehicle, the vehicle movement data including a vehicle speedof the vehicle at a vehicle location in the mitigation road segment atthe current timestamp; and determining the vehicle density of themitigation road segment at the current timestamp based on the vehiclespeed of the vehicle at the current timestamp and the first trafficdiagram associated with the roadway in the unimpeded traffic condition.14. The method of claim 6, wherein determining the target traffic statefor the upstream portion of the mitigation road segment includes:determining the target traffic state on the first traffic diagramassociated with the roadway in the unimpeded traffic condition based onan average vehicle density of the mitigation road segment at a futuretimestamp, and wherein the target mitigation speed transitions theupstream portion of the mitigation road segment to the target trafficstate having the average vehicle density of the mitigation road segmentat the future timestamp.
 15. The method of claim 6, wherein determiningthe target mitigation speed for the first controllable vehicle includes:determining a tangent line including the target traffic state on thefirst traffic diagram associated with the roadway in the unimpededtraffic condition and being tangent to the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition; determining an initiation traffic state of the one or moreopen lanes on the second traffic diagram associated with the one or moreopen lanes in the impeded traffic condition based on the tangent line,the traffic state of the first open lane being the initiation trafficstate of the one or more open lanes; and determining the targetmitigation speed for the first controllable vehicle based on a slope ofa state transition line, the state transition line including theinitiation traffic state on the second traffic diagram associated withthe one or more open lanes in the impeded traffic condition and thetarget traffic state on the first traffic diagram associated with theroadway in the unimpeded traffic condition.
 16. A system comprising: oneor more processors; one or more memories storing instructions that, whenexecuted by the one or more processors, cause the system to: determine afirst controllable vehicle traveling along a mitigation road segment ofa roadway; determine a control lane in the mitigation road segment, thecontrol lane including the first controllable vehicle and beingimpedible by the first controllable vehicle; determine a first open lanein the mitigation road segment, the first open lane being adjacent tothe control lane in the mitigation road segment; and apply a targetmitigation speed to the first controllable vehicle in the control lane,the target mitigation speed being based on a traffic state of the firstopen lane, the target mitigation speed adjusting a traffic stream thatflows through the first open lane to mitigate traffic congestion locateddownstream of the mitigation road segment.
 17. The system of claim 16,wherein the target mitigation speed increases a passing flow rate atwhich the traffic stream flowing through the first open lane passes thefirst controllable vehicle travelling at the target mitigation speed inthe control lane.
 18. The system of claim 16, wherein the instructions,when executed by the one or more processors, further cause the systemto: determine a second open lane in the mitigation road segment; andwherein the target mitigation speed maximizes an overall passing flowrate at which the traffic stream flowing through the first open lane anda traffic stream flowing through the second open lane pass the firstcontrollable vehicle travelling at the target mitigation speed in thecontrol lane.
 19. The system of claim 16, wherein to determine the firstopen lane in the mitigation road segment includes: determining one ormore proximate controllable vehicles located proximate to the firstcontrollable vehicle in the mitigation road segment; and determining thefirst open lane in the mitigation road segment, the first open laneexcluding the one or more proximate controllable vehicles and beingunimpedible by the one or more proximate controllable vehicles.
 20. Thesystem of claim 16, wherein the instructions, when executed by the oneor more processors, further cause the system to: determine a proximatecontrollable vehicle located proximate to the first controllable vehiclein the mitigation road segment; determine an impedible lane in themitigation road segment, the impedible lane including the proximatecontrollable vehicle and being impedible by the proximate controllablevehicle; and apply the target mitigation speed to the proximatecontrollable vehicle in the impedible lane.
 21. The system of claim 16,wherein the instructions, when executed by the one or more processors,further cause the system to: determine one or more open lanes and one ormore impedible lanes in the mitigation road segment, the one or moreopen lanes including the first open lane; generate a first trafficdiagram associated with the roadway in an unimpeded traffic condition,the control lane and the one or more impedible lanes in the mitigationroad segment being unimpeded in the unimpeded traffic condition;generate a second traffic diagram associated with the one or more openlanes in an impeded traffic condition, the control lane and the one ormore impedible lanes in the mitigation road segment being impeded in theimpeded traffic condition; determine a target traffic state for anupstream portion of the mitigation road segment, the upstream portion ofthe mitigation road segment being located upstream of the firstcontrollable vehicle; and determine the target mitigation speed for thefirst controllable vehicle based on the first traffic diagram associatedwith the roadway in the unimpeded traffic condition, the second trafficdiagram associated with the one or more open lanes in the impededtraffic condition, and the target traffic state for the upstream portionof the mitigation road segment.
 22. The system of claim 21, wherein togenerate the first traffic diagram associated with the roadway in theunimpeded traffic condition includes: monitoring traffic data of theroadway; computing one or more traffic metrics associated with theroadway based on the traffic data of the roadway; determining one ormore roadway properties of the roadway; generating the first trafficdiagram associated with the roadway in the unimpeded traffic conditionbased on an initial traffic diagram, the one or more traffic metricsassociated with the roadway, and the one or more roadway properties ofthe roadway; and wherein the first traffic diagram indicates arelationship between a flow rate and a vehicle density on the roadway ora relationship between a vehicle speed and the vehicle density on theroadway in the unimpeded traffic condition.
 23. The system of claim 22,wherein the traffic data of the roadway includes one or more of a flowrate, a vehicle density, and a vehicle speed associated with a pluralityof road segments of the roadway at a plurality of timestamps; the one ormore traffic metrics associated with the roadway includes one or more ofa roadway capacity, a capacity vehicle density corresponding to theroadway capacity, and a jam vehicle density associated with the roadway;and the one or more roadway properties of the roadway includes one ormore of a speed limit and a number of lanes associated with the roadway.24. The system of claim 21, wherein to generate the second trafficdiagram associated with the one or more open lanes in the impededtraffic condition includes: monitoring traffic data of the roadway;computing one or more traffic metrics associated with the roadway basedon the traffic data of the roadway; computing one or more trafficmetrics associated with the one or more open lanes based on the trafficmetrics associated with the roadway and a number of open lanes in themitigation road segment; determining one or more roadway properties ofthe one or more open lanes; generating the second traffic diagramassociated with the one or more open lanes in the impeded trafficcondition based on an initial traffic diagram, the one or more trafficmetrics associated with the one or more open lanes, and the one or moreroadway properties of the one or more open lanes; and wherein the secondtraffic diagram indicates a relationship between a flow rate and avehicle density in the one or more open lanes or a relationship betweena vehicle speed and the vehicle density in the one or more open lanes inthe impeded traffic condition.
 25. The system of claim 21, wherein todetermine the target traffic state for the upstream portion of themitigation road segment includes: determining a traffic wave on theroadway and one or more propagation parameters of the traffic wave;determining a vehicle density of the mitigation road segment at acurrent timestamp; estimating an average vehicle density of themitigation road segment at a future timestamp based on the vehicledensity of the mitigation road segment at the current timestamp and theone or more propagation parameters of the traffic wave; and determiningthe target traffic state for the upstream portion of the mitigation roadsegment based on the average vehicle density of the mitigation roadsegment at the future timestamp.
 26. The system of claim 25, wherein todetermine the traffic wave on the roadway and the one or morepropagation parameters of the traffic wave includes: receiving vehiclemovement data of one or more vehicles located on the roadway at aplurality of timestamps; determining a plurality of vehicle densitydistributions associated with the roadway at the plurality of timestampsbased on the vehicle movement data of the one or more vehicles locatedon the roadway at the plurality of timestamps and the first trafficdiagram associated with the roadway in the unimpeded traffic condition;and determining the traffic wave on the roadway and the one or morepropagation parameters of the traffic wave based on the plurality ofvehicle density distributions associated with the roadway at theplurality of timestamps.
 27. The system of claim 26, wherein the vehiclemovement data of the one or more vehicles located on the roadway at theplurality of timestamps includes one or more of a vehicle location, avehicle speed, and a vehicle lane of a vehicle among the one or morevehicles at a corresponding timestamp among the plurality of timestamps;and the one or more propagation parameters of the traffic wave includesone or more of a propagation speed, a propagation distance, a coveragearea of a traffic stop region associated with the traffic wave, and acoverage area of a traffic moving region associated with the trafficwave.
 28. The system of claim 25, wherein to determine the vehicledensity of the mitigation road segment at the current timestampincludes: receiving vehicle movement data of a vehicle, the vehiclemovement data including a vehicle speed of the vehicle at a vehiclelocation in the mitigation road segment at the current timestamp; anddetermining the vehicle density of the mitigation road segment at thecurrent timestamp based on the vehicle speed of the vehicle at thecurrent timestamp and the first traffic diagram associated with theroadway in the unimpeded traffic condition.
 29. The system of claim 21,wherein to determine the target traffic state for the upstream portionof the mitigation road segment includes: determining the target trafficstate on the first traffic diagram associated with the roadway in theunimpeded traffic condition based on an average vehicle density of themitigation road segment at a future timestamp, and wherein the targetmitigation speed transitions the upstream portion of the mitigation roadsegment to the target traffic state having the average vehicle densityof the mitigation road segment at the future timestamp.
 30. The systemof claim 21, wherein to determine the target mitigation speed for thefirst controllable vehicle includes: determining a tangent lineincluding the target traffic state on the first traffic diagramassociated with the roadway in the unimpeded traffic condition and beingtangent to the second traffic diagram associated with the one or moreopen lanes in the impeded traffic condition; determining an initiationtraffic state of the one or more open lanes on the second trafficdiagram associated with the one or more open lanes in the impededtraffic condition based on the tangent line, the traffic state of thefirst open lane being the initiation traffic state of the one or moreopen lanes; and determining the target mitigation speed for the firstcontrollable vehicle based on a slope of a state transition line, thestate transition line including the initiation traffic state on thesecond traffic diagram associated with the one or more open lanes in theimpeded traffic condition and the target traffic state on the firsttraffic diagram associated with the roadway in the unimpeded trafficcondition.
 31. A method comprising: determining a first controllablevehicle and a second controllable vehicle traveling along a mitigationroad segment of a roadway; monitoring a distance between the firstcontrollable vehicle and the second controllable vehicle; determiningthat the distance between the first controllable vehicle and the secondcontrollable vehicle satisfies a proximity distance threshold at acurrent timestamp; responsive to determining that the distance betweenthe first controllable vehicle and the second controllable vehiclesatisfies the proximity distance threshold at the current timestamp,determining a control lane and an impedible lane in the mitigation roadsegment, the control lane including the first controllable vehicle andbeing impedible by the first controllable vehicle, the impedible laneincluding the second controllable vehicle and being impedible by thesecond controllable vehicle; determining an open lane in the mitigationroad segment, the open lane being adjacent to the control lane in themitigation road segment; and applying a target mitigation speed to thefirst controllable vehicle in the control lane and the secondcontrollable vehicle in the impedible lane, the target mitigation speedbeing based on a traffic state of the open lane, the target mitigationspeed adjusting a traffic stream that flows through the open lane tomitigate traffic congestion located downstream of the mitigation roadsegment.
 32. The method of claim 31, wherein determining the firstcontrollable vehicle and the second controllable vehicle includes:determining the first controllable vehicle that has a distance betweenthe first controllable vehicle and the traffic congestion satisfying acongestion distance threshold; and determining the second controllablevehicle that has a distance between the second controllable vehicle andthe first controllable vehicle satisfying an initial vehicle distancethreshold.